Kirsty Toomey, 25, underwent surgery on Monday to fix damage to a section of her neck, which had previously been fused.

She will be forced to wear a neck brace for the next three months as part of her recovery.

Late last year, Ms Toomey had a 360-degree fusion, at the front and back, of the vertebrae in her neck.

Scans upon her admission to hospital on Sunday showed the back part of the fusion had separated.

Ms Toomey's lawyers, from Ben Aulich & Associates, believe the injury may have been caused by a "rough ride" while in custody.

A rough ride is when a police wagon – which has no seatbelts or restraints in the back – is driven erratically so a detainee is thrown violently about.

Ms Toomey had a warrant out for her arrest for failing to appear in court on a driving-while-disqualified charge.

ACT Policing confirmed Ms Toomey had been arrested about 10.20am on Sunday and taken to the ACT watch-house.

"The female complained of a medical condition and as a result was transported, by ACT Ambulance Service, to the Canberra Hospital for treatment," the police said.

"For privacy reasons we are unable to comment on the female's medical condition or history."

ACT Emergency Services received a call about 11.45am, and an ambulance arrived at 12.05pm.

Paramedics assessed a female patient then departed with her about 12.15pm and arrived at Canberra Hospital at 12.27pm.

Ms Toomey's lawyer, Peter Woodhouse, said she had gone to the Alexander Maconochie Centre on Sunday morning to visit an inmate when police arrested her.

"She was co-operative and not handcuffed," Mr Woodhouse said.

"When police went to put her in the back of the paddy-wagon, she told them about her neck problem and asked whether she could sit in the front.

"They commented on the scar on her neck from the previous operation, which was then discussed briefly."

But Mr Woodhouse said officers refused her request and put her in the back of the vehicle.

He said she became concerned when police started to drive, so crouched down in an attempt to brace herself.

"The vehicle accelerated quickly, she thinks over a speed bump, and she bounced upwards, the back of her neck connecting with the top of the pod," Mr Woodhouse said.

"She was in immediate pain. She asked the police to stop repeatedly, they didn't."

Ms Toomey alleges she could not lift her neck or head and could not get out of the vehicle upon arriving at the ACT watch-house about 11am.

She complained of severe pain and asked to see a doctor, but was told she would have to wait, Mr Woodhouse said.

Ms Toomey was then placed in a cell and given blankets when she asked for a pillow.

She alleges she complained on multiple occasions and asked to see a doctor.

"She believes she passed out from the pain [and] was woken by the doctor touching her face, " Mr Woodhouse said.

"The doctor questioned and examined her briefly [before telling] police she needed an ambulance and had to be taken to hospital immediately."

Mr Woodhouse said he had requested copies of CCTV footage and records from the ACT watch-house, but the AFP had not yet provided the material.

"I am very concerned somebody can suffer such a serious injury in police custody and despite repeated requests for medical assistance, has to wait many hours to be seen by a doctor."

Ms Toomey was granted bail by Magistrate Robert Cook during an unopposed bedside application on Wednesday.

The 25-year-old expects to be released from hospital to begin her recovery this weekend.