This Canberra firefighter, speaking on the condition of anonymity, tells an all too common tale of the impact overtime has on his life outside work.

Staff across the ACT's emergency services are working increasing amounts of overtime, and it's coming at a growing personal cost to them and a mounting monetary cost to taxpayers.

The territory's emergency services workers were paid $15,409,214.92 of overtime, penalties and allowances in 2017-18, on the back of significant increases in the past five financial years across the policing, firefighting and paramedic services.

That was an increase of 52.5 per cent from the annual bill in 2013-14, which was $10,106,686.84.

Four firefighters spoke to the Sunday Canberra Times on condition of anonymity following revelations that ACT Fire and Rescue's annual overtime bill had increased by $800,000 since a plan to cut back on the practice was introduced in 2016 because of what was called an "unsustainable" overtime bill of $4.1 million.

One described having his young son constantly ask, "Dadda going to work?" because it was so common for the firefighter to be recalled to duty, even when he had indicated he was unavailable.

"The best way to explain it is you make yourself available for the shifts you could work on your days off, then that's what they call you for," he said. "But at the moment, I get called almost every shift.

"Even though I'm unavailable, they're down to their last chance to see who else is free, because they've exhausted all options.

"Sometimes I have to hand off my child to see if my mum can take him, and go and help out."

Another said his son's regular reaction to the news that his dad had to go to work was, "Again!? But you worked last night."

"Shifts have to be filled," he said.

"There was one set of four days where I think I worked five extra shifts in four days.

"It equated to about 62 hours of extra work. That's 62 extra hours I'm not at home."

All four believed the extra hours could have an impact on the quality of their work, as well as leaving them exhausted and leading to a poor work-life balance.

Asked what the solution was, one firefighter replied: "More staff. It's simple."

Their representatives agree, with the United Firefighters Union pushing for an extra 204 urban firefighters in the ACT as part of a dispute with the Emergency Services Agency over firefighters' next enterprise bargaining agreement.

Steve Geerdink, a veteran of 35 years as a firefighter before his retirement in late January, said he had seen spikes in overtime before, "but nothing like this".

He said the extra pay was great, but overtime undoubtedly took a toll on firefighters' wellbeing. He said it seemed to be getting worse.

"I know had an incidence where, in a 48-hour period, I worked all but six hours of that," Mr Geerdink said.

"It takes a toll. You think about being in the one place, doing the same thing for nearly two days straight, you go a bit stir crazy.

"You don't have to do [overtime]. It's not compulsory, but you know if you don't do it, they're going to pick up the phone for the next person... it all comes back to being understaffed."

ACT Fire and Rescue's annual spending on overtime has more than doubled since 2013-14, rising from $2 million then to $4.9 million last financial year.

Chief officer Mark Brown has told firefighters more staff are being recruited as quickly as possible, "but in the short to medium-term, vacancies will continue to need to be covered by overtime".

He said there had been a higher than expected number of retirements recently, as well as a number of firefighters who had taken long-term leave or were medically unfit for frontline duties.

Police officers and their union representatives share firefighters' concerns about understaffing and the impact on individuals.

In January, it was revealed the ACT had the lowest number of police officers per 100,000 residents in any Australian jurisdiction.

ACT Policing had 677 sworn officers at last count, but the number was above 700 five years ago.

The force spent $9,068,000 on overtime, penalties and allowances in 2017-18, up more than 35 per cent from $6,711,000 in 2013-14.

A long-serving ACT Policing officer said he felt the ACT government undervalued the territory's cops.

"They get a Rolls Royce police service for the price of a Toyota Corolla, which like ACT Policing, is reliable, keeps on going, is tough to destroy and runs off the smell of an oily rag," said the officer, who spoke on condition of anonymity.

"We are thankful for the money spent on initiatives, but you still require a police officer to operate this equipment.

"Last time I checked, a smartphone couldn't drive a police car, a taser can't pass a death message to a family and then support them, and a protective vest can't write a traffic infringement notice and promote road safety messaging."

Australian Federal Police Association president Angela Smith said fatigue levels within ACT Policing were "very high and hugely concerning".

Ms Smith said this lack of personnel meant officers were being offered excessive amounts of overtime, and often taking it because they were loyal to their own detriment.

"They want to work, they want to help the community and they don't want to let their colleagues, mates and the community down," she said.

"They often put their hands up to work overtime when in reality they should be spending time away from the operational policing environment and recuperating with their family and friends.

"The cold hard reality of this is that members are falling over due to fatigue and this leads to a myriad of issues and eventually something snaps and 99 times out of 100 it's the poor police officer.

"They are suffering, both mentally and physically and it really needs to be addressed and quite quickly."

Ms Smith put an increase in exhaustion and fatigue within ACT Policing down to a growing population, an increase in calls and a lack of police numbers.

She said police officers were more likely than most to develop mental health issues like post-traumatic stress disorder, "and working them to the bone doesn't help".

"The ACT government has been squeezing blood from the stone for years and that blood has nearly run out," Ms Smith said.

"It's time for the ACT government to take some responsibility for the current state-of-affairs and commit to putting more police officers on the frontline via increased funding to ACT Policing."

Like the police officer who spoke to the Sunday Canberra Times, Ms Smith welcomed initiatives that provided more advanced tools of the trade for police officers, but said they were useless if the police officer holding them could not work because of increasingly common fatigue or mental health issues.

She slammed Police and Emergency Services Minister Mick Gentleman for allowing police numbers to decline, but trumpeting the arrival of new ambulances and paramedics in a media release in January.

"It really doesn't make much sense and it doesn't pass the 'pub test' for the members of ACT Policing and the AFPA," Ms Smith said.

The Sunday Canberra Times sought comment from Mr Gentleman, who was overseas.

In his absence, an ACT government spokesman said the government would provide $167 million for ACT Policing in the 2018-19 budget, up from $150 million in 2013-14.

He said the government had supported a range of policing initiatives in this time.

"We know that Canberrans feel safe. The ACT experiences low crime rates compared to other jurisdictions and rates have been stable over the last decade," the spokesman said.

"The Canberra community also reports high levels of satisfaction with ACT Policing.

"The ACT government will continue to work closely with ACT Policing to identify where to target resourcing and on the size our police force to ensure we remain one of the safest places to live."

An ACT Policing spokesman said the service recognised the need to limit overtime, but as an incident response agency, some level of overtime should be expected.

He said the need for overtime was influenced by factors including critical incidents, significant investigations, responses to incidents near the end of a rostered shift and major sporting or entertainment events.

Unplanned absences, court attendance and the need to provide support to people involved in family violence and mental health incidents could also contribute to overtime.

The spokesman said ACT Policing had 87 first-year recruits and was expecting to receive another 25 in April, plus 20 transitional recruits in November.

The ACT Ambulance Service's overtime bill increased by more than 60 per cent between 2013-14 and 2017-18, rising from $1,395,686.54 to $2,241,214.92.

An Emergency Services Agency spokeswoman said the increase was "linked to a consistent rise in ambulance demand and wage increases".

"In order to provide a 24-hour service to the ACT community, overtime is necessary to maintain operational rosters and to cover for surge activities, for example special events," she said.

"[The ACT Ambulance Service] is reviewing some shift arrangements to minimise end-of-shift case generated overtime.

"At this time, the [ACT Ambulance Service] overtime allocation is not considered excessive."

The spokeswoman said 53 new paramedic positions had recently been funded by the ACT government, with eight of those new staff starting last year.

Another 15 of those had started in the last two months and had therefore not yet had a significant impact on the operational roster.

"The next 30 paramedics will be employed over the next 12 months and will move onto the roster over this time," she said.