This article is more than 2 years old

This article is more than 2 years old

A bill to restore the territories’ right to legislate for voluntary euthanasia looks set to pass the Senate, according to its architect, the Liberal Democrat David Leyonhjelm.

With at least 40 senators likely to support the bill, currently being debated in the Senate, proponents are confident it will pass this week, creating a dilemma for the Turnbull government about whether to allow a vote in the lower house.

Leyonhjelm has accused the government of reneging on a deal to allow a free vote on the issue. The accusation came as several ministers anonymously warned Malcolm Turnbull – in comments to the Australian – not to allow a vote that would likely see the bill pass.

The bill to allow the Northern Territory and Australian Capital Territory to legislate for euthanasia – reversing a ban imposed by the commonwealth in 1997 – has support from at least 18 Labor senators, the nine Greens, eight crossbench senators and a small but growing group of Coalition senators. It needs 39 to pass the Senate.

On Monday the education minister, Simon Birmingham, confirmed he would support the bill, joining Liberals Ian Macdonald and Nigel Scullion, and National Steve Martin.

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“Just because the federal parliament doesn’t like what a state or territory does isn’t sufficient justification to trample over their right to do it,” Birmingham said.

“Australians with a terminal illness should have a right to die with dignity, ideally with effective palliative care, but with sufficient safeguards, that right, in extreme cases, should also extend to voluntary euthanasia.”

Leyonhjelm told Guardian Australia the “numbers still look good” as debate progressed on Tuesday.

Leyonhjelm believes he secured the government’s agreement for a free vote in both houses in exchange for support to reinstitute the Australian Building and Construction Commission, although the government has now equivocated on whether it will allow the bill to come to a vote in the lower house.

Leyonhjelm accused Turnbull of refusing a vote in the lower house to contain “internal Liberal conflict”, heeding the warnings of conservatives that to do so would “open wider fractures within the party”.

“My view is a deal’s a deal – the prime minister’s internal problem is not my problem.”

Leyonhjelm suggested he would need to “find a bigger stick” to force the government’s hand, such as finding a bill it “really wants to pass” and making his support conditional on a lower house vote on euthanasia.

The ACT Labor senator David Smith told Guardian Australia that although he opposed euthanasia he would support the bill because the ACT assembly “has a right to conduct a mature and respectful debate about this issue”.

The ACT Liberal senator Zed Seselja argued in an opinion piece that Labor senators had supported overriding the territories’ laws in other areas, such as mandatory sentencing.

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He warned that he had “no doubt assisted suicide will become law in the ACT” if the bill passes and that “safeguards have time and again been eroded in other jurisdictions”.

In Senate debate on Tuesday, Labor senator Kristina Keneally said she did not have an in-principle opposition to euthanasia and announced she would vote for the bill.

Keneally added that she is concerned about safeguards on voluntary euthanasia and whether parliament would “move to legalise euthanasia before it considers the adequacy of palliative care”.

“However the legislation does not ask us to approve or disapprove of euthanasia – but whether territories should have power to determine the question for themselves,” she said.

Liberal senator Eric Abetz argued that although the commonwealth should use its power to overrule the territories sparingly, it should do so in “matters of life and death”.

He asked senators who support the bill on the basis of “territory rights” to consider whether they would oppose a bill to allow territories the power to institute the death penalty.

The bill to restore territories’ rights to legislate for euthanasia is opposed by 16 Coalition senators, Katter Australia party’s Fraser Anning and Australian Conservatives’ Cory Bernardi. Labor senators Jacinta Collins and Helen Polley are also presumed to oppose it but did not respond to requests to clarify their position.