Refugee advocates are urging crossbench senators to resist any attempts to tinker with medical evacuation laws that the federal government is desperate to scrap.
Prime Minister Scott Morrison has described abolishing the so-called "medevac" laws as one of his most pressing priorities.
The laws, which passed against his government's wishes earlier this year, gave doctors a greater say in granting sick refugees medical transfers.
With federal parliament returning this week for the first time since the May 18 election, advocates are ramping up their lobbying efforts.
Former MP Kerryn Phelps, who was a driving force behind the legislation, has returned to Canberra to convince senators to keep the system intact.
Professor Phelps says medical issues among refugees on Manus Island and Nauru are only getting worse, arguing there is no evidence to unwind the laws.
Cabinet minister Mathias Cormann, the government's chief negotiator in the Senate, still has every intention of repealing the legislation.
However, much of this week will be taken up by formalities and condolences for former prime minister Bob Hawke.
"We essentially have only got one day of business in the Senate, and I suspect that ... will be taken up with legislating our income tax relief," Senator Cormann told reporters on Monday.
"But it (repealing the legislation) will happen soon."
Labor frontbencher Tony Burke said the government had made "no case at all" as to why the laws should be scrapped.
Mr Burke described Home Affairs Minister Peter Dutton as "the boy who cried wolf".
"The exaggerations that we've seen, the reopening of Christmas Island, being told that this was going to open the floodgates - all their tales of woe have not materialised," Mr Burke told reporters.
"We've got a law in place that says if someone in our care isn't well, they need to get medical attention."
Federal parliament will sit for another two weeks later this month, before taking a five-week winter break.
