A majority of Australian voters back the medevac regime in its current state or believe it should be more compassionate, according to the latest Guardian Essential poll.

The new snapshot of positive voter sentiment, which lands as the critical medevac repeal vote looms in the Senate, has a quarter of the sample saying the medevac procedures do not go far enough in providing humane treatment for people in offshore detention.

Despite the Morrison government arguing for months that medevac creates national security risks, it appears a number of voters aren’t listening to the rhetoric. In February, only 16% of the sample were of the view the medevac system wasn’t compassionate enough, and that’s now up to 25%.

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A further 37% of the sample argue the medevac procedures strike a balance between strong borders and humane treatment for people on Nauru and Manus Island, which is the same result as February. While more than 60% of the sample appear to favour the status quo or something stronger, just under a quarter of the sample (22%) believes the regime weakens Australia’s borders and 17% are unsure.

With federal parliament now in its final two sitting weeks before the summer break, the Morrison government has listed medevac repeal for Wednesday in the Senate.

The medevac laws, passed when the Coalition governed in minority last year, allow for Australia-based doctors to recommend a refugee or asylum seeker offshore be transferred to Australia for care. The minister can refuse if he or she disagrees with the clinical assessment – in which case it goes to the independent medical panel for review – or on security or criminal grounds. The panel cannot override vetoes based on security or criminal concerns.

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Scott Morrison and Peter Dutton want the system gone, and the home affairs minister has been ramping up the negative rhetoric in advance of the decisive vote, but Labor, the Greens, key crossbenchers and most relevant stakeholders, including the medical profession, oppose a repeal of the laws.

The Coalition will only succeed in repealing the regime if it wins backing from the Tasmanian independent senator Jacqui Lambie, who has been running down the clock for months while she deliberates.

Lambie, who is understood to want asylum seekers currently offshore resettled more quickly, met Scott Morrison on Monday morning to discuss options. The Centre Alliance senator Rex Patrick said on Monday Lambie did not want to repeal medevac, but was exploring whether or not amendments could be made to the system.

“I have spoken to Jacqui, and she is not supporting a repeal of the legislation, she is considering amending the legislation,” Patrick told Sky News as Lambie met the prime minister. “I don’t know the details of what she is proposing and I understand she is talking with the government, but it is my understanding that she is not seeking to repeal that bill”.

The government is yet to decide whether it will countenance any concrete proposition Lambie puts to it, or whether it will force the vote regardless this week to bring an end to months of uncertainty.

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Medical and refugee advocacy groups are working the corridors of the parliament in advance of Wednesday’s vote. David Manne, the executive director of Refugee Legal, said on Monday the medevac procedures were implemented for a reason, and that reason was the Coalition had failed to provide proper medical care to people on Nauru and Manus Island.

Manne said the laws were absolutely necessary and there was no reason to repeal them. “Removing a fair, medically-led process for accessing life-saving treatment is inhumane and completely unjustified. Repealing the medevac laws increases the risk of more people dying on Nauru and in PNG”.

The message was echoed by the Royal Australasian College of Physicians. The RACP president, Mark Lane said: “The medevac legislation allows medical experts to make decisions about healthcare for seriously ill individuals and ensure that they receive the medical treatment that they need in a clinically appropriate timeframe”.

“We know that previous delays and failures to transfer ill asylum seekers resulted in preventable suffering. Medical decisions should be made by medical professionals. As doctors, we continue to put patients first and uphold the basic human right to healthcare”.