In 2015, 2420 fines were issued to drivers parking illegally in a mobility parking space, up on 2014 when 2334 were issued and 2013 with 2272.

Conversely, the number of drivers who successfully challenged their infringements is on the decline.

In 2013, 735 fines were withdrawn, dropping to 703 in 2014 and so far just 587 people have had their fine from 2015 withdrawn, but a spokesman for Access Canberra said some requests were still being accessed.

Advocacy for Inclusion general manager Christina Ryan said the "unusual" case of a woman with paraplegia having a fine withdrawn for parking in a disabled parking space without her ACT mobility parking permit placed in the sleeve of the Australian disability parking permit, had sparked conversations in the disability community and highlighted the need for better training for parking rangers.

She said permit-holders often chose not to display the permit permanently in the window to avoid visibility issues and instead placed it on the dashboard when the car was parked.

"A lot of people with disabilities can't reach the other side [of the windscreen]," she said.

"We're not all the same, we don't all fit in a job lot … permits can look different, it's the date that's important."

To be eligible for a mobility parking permit in the ACT a person must: be unable to walk 100 metres, require the use of mobility aid or be blind.

The paraplegic woman, who was fined at Woden Westfield, called for a two-tier colour-coded system of mobility parking giving priority to people who are totally reliant on wheelchairs or scooters.

"I do not believe they should be treated the same as having weak legs or some other ailment," she said.

"We shouldn't have to compete with elderly people with carers who can still walk independently but are limited in distance."

Ms Ryan said there had been suggestions to introduce a system similar to Queensland, with wider spaces for people who relied on mobility equipment and standard-sized disabled parking spaces for those who did not.

But there was a risk it would limit space further and it would be difficult to split permit-holders into the two categories as some people's abilities could change day to day.

Ms Ryan said the low ratio of about two mobility parking spaces for every 100 standard spaces was a "big problem".

"More than 2 per cent of the population have a disability plus there's the temporary permit-holders who aren't counted by the ABS," she said.

"About 20 per cent of the Australian population has a disability."

While not all of the 20 per cent needed a permit, Ms Ryan said with the ageing population the proportion of people only able to walk short distances or requiring aids was increasing, causing demand to grow.

Locations such as doctors' surgeries or suburbs in the inner north and south – where there was a higher proportion of elderly people – were hotspots, but Ms Ryan said the parking ratio remained the same.

"The guys in TAMS are pretty together on things, they're always willing to install extra spaces, but we still have a clear shortage of disabled parking in Canberra and across the country," she said.

She rejected suggestions for the ACT to follow the lead of NSW and introduce photo identification on disability parking permits to stop people rorting the system.

"How many people would be happy to stick a picture of themselves on their dashboards?" she said.

"There is an enormous amount of rorting but it's not worth risking someone's privacy and safety."

Instead she believes better education was needed to discourage people from fraudulently using the permits.

Ms Ryan said people illegally parking in the shared zones marked with yellow lines to give more space between disabled parking spaces was another common issue permit-holders faced.