On Tuesday morning, the Southcare Toll rescue helicopter was at last able to winch the bushwalker to safety, after fog hampered efforts overnight.

ACT Policing search and rescue teams found the woman in bushland west of Canberra late on Monday.

An ESA spokesman said the woman was suffering a suspected broken ankle and had been taken to Canberra Hospital in a stable condition.

Steep terrain coupled with fog overnight made it impossible to winch the woman out of the reserve by chopper on Monday night.

"She was in an awkward spot so crews had to move her a short way to somewhere flatter so the chopper could get her out, but all's worked out, she's been rescued.

"Now off to the pub for a coffee! It was a hell of a night apparently."

Police said the woman took a tumble while out walking on Monday afternoon. She had tried to take the shortest route back to the Mountain Creek carpark, but eventually stopped due to the pain of the injury.

"Fortunately, she had signal on her phone and she was able to call triple zero," an ACT Policing spokesman said.

"Our crews first heard her at about 7.30pm and we got hands on her at about 8.15."

Crews stayed with the woman overnight. She was found more than 2km from the northern end of the carpark.

"We were really lucky in this case to be communicating with her the whole time and she had food and water with her," the spokesman said.

Tackling steep, challenging terrain was the "bread and butter" of police search and rescue teams, he said.

"But we can't control the fog."

As the skies cleared on Tuesday, a second rescue attempt with the chopper kicked off. A paramedic was dropped down to the scene first at about 8:30am.

It is understood the woman was alone at the time of her fall.