The union says it was promised a boost to staffing and resources for ACT Fire and Rescue before the last election, but United Firefighters Union secretary Greg McConville remains concerns little action has been taken 15 months on.

Emergency services minister Mick Gentleman maintains the government is funding an extra recruitment college for an extra 18 staff, set to begin shortly, as well as launching an extra crew for the service in Ainslie.

But Mr McConville said that was not enough, saying the expected retirement of up to 20 firefighters expected in the next year, and those on leave for injuries and long service means an extra two colleges are needed this year.

"Whilst official data says we've got about 340 firefighters, that's how many are employed, but we have an ageing workforce and with that ageing workforce, people accrue leave and are entitled to take it up," he said.

"Other members who've served up to 40 years as firefighters have also succumbed to illness, post-traumatic stress disorder and musculoskeletal injuries, and they are entitled to their leave, but the fact is there needs to be an adjustment to make up the numbers."

In its budget submission, the UFU has also urged the government to put up the cash for a $1.4 million combined aerial pumper to help fight fires in buildings up to four storeys, $3.1 million for associated training, $1.3 million for more higher standard uniforms and $19 million for a new city fire station.

Mr McConville said he was "happy to negotiate" with government about the union's calls, but that it was hard to choose what you would say no to, given there was "no way to put shortcuts on safety".

He said while the government had also committed funding in last year's budget for a $200,000 feasibility study for a new city fire station, it seemed "a lot of funding has gone into thinking about it, but not doing it".

While Mr Gentleman acknowledged fire fighters were under greater pressure in recent years due to population growth, he said the government was providing "more and more" resources for the service.

But he said the government would deliver on its election promises, also suggesting he would have more to say about another potential aerial pumper for the ACT "shortly".

He also said the government had begun a new 'lateral recruitment' process last year, which allows for additional recruitment of fire fighters from recognised services on an 'as needs' basis to help bolster staffing.

Emergency Services Agency commissioner Dominic Lane said while the service was under "increased demand", he believed the service had the continued support of the government when it came to funding.