As federal parliament returns for its final sitting fortnight of the year, the Morrison government will attempt to get its bill to repeal the laws through the Senate.

The Coalition has been locked in long-running negotiations with key crossbenchers in order to scrap the legislation, which provides a pathway for asylum seekers from Manus Island and Nauru to come to Australia for medical treatment.

Nearly 170 people have been brought to Australia under Medevac so far.

The latest quarterly report from the Independent Health Advice Panel revealed doctors upheld Home Affairs Minister Peter Dutton's decision to refuse the transfer of 45 people, and approved 12 transfers

But it highlighted delays in advice from doctors being handed to the minister.

It also raised concerns about detainees being unable to be medically evacuated from Nauru, despite the existence of the scheme.

However despite the teething problems, refugee advocates are afraid of what will happen if the scheme is revoked.

Canberra nun Sister Jane Keogh began helping the detainees on Manus Island by sending mobile phones in 2015. She's one of many Canberrans who volunteer their time to support those stuck in offshore detention through the group Manus Lives Matter.

"If Medevac fails, we're going to fall into a heap. I don't know what will happen to the guys but I know what will happen here - anger and frustration," Sr Keogh said.

Before Medevac, advocates would have to fight for every medical transfer in court.

While their cases were largely successful, the cost and the time it took was a problem.

Now, that process is much more straightforward. Sixteen asylum seekers flew into Melbourne on one flight for medical treatment a fortnight ago, a situation which would have been unimaginable before.

However it is still difficult to get asylum seekers to Australia for collections of ailments that may seem minor, but collectively can make life miserable.

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Many of the men Sr Keogh speaks to suffer from depression and other mental illnesses. Many also have an h. pylori infection, which causes stomach ulcers and can lead to stomach cancer if left untreated.

"It's resistant to many antibiotics, so even if you were in Australia, you have to go to the doctor who would monitor how it responds to different antibiotics over time," she said.

Some nights, the men can hardly speak. Many can't sleep, because they're covered in rashes or are on medications with contraindications.

Sr Keogh does what she can for them. Men send her photos of their prescription medications, and she pores over them with a psych nurse friend to work out what might be the problem.

"It's hard for us because we're not doctors but we're called to be each night," Sr Keogh said.

The medical treatment available on Manus is appalling, she said. One asylum seeker who had a problem with nerves in his hand has lost movement to his whole arm since his operation. Another man with nasal problems has had repeated procedures over the past three years, but has yet to find relief.

'It's something in Australia you'd go to the doctor for and have minor surgery within a month," Sr Keogh said.

One man has suffered with a "great, protruding, bleeding" fistula for two years. When he eventually saw a doctor, he was given tablets.

"Again that wouldn't happen in Australia," she said.

Helping these men has taken its toll on Sr Keogh. Like many of the Canberrans supporting the men on Manus, she has trouble sleeping. She receives counselling each month to debrief.

But the threat of going back to the previous system, where every medical evacuation was hard fought and hard won, exhausts and frightens her.

"The helpers in Australia really need these guys to be somewhere where they can get proper help," Sr Keogh said.