Crossbench libertarian senator David Leyonhjelm is threatening to block legislation unless the Turnbull government allows the whole parliament a conscience vote on his euthanasia bill.
The bill would allow the territories – the Northern Territory and the ACT – to legislate their own euthanasia policies.
ACT chief minister Andrew Barr and NT chief minister Michael Gunner took out a full-page ad on Monday, urging the Senate to approve the bill on Tuesday.
“Voting for this bill doesn’t mean there will be assisted dying in the NT or the ACT,” the ad reads.
“It will simply give Territorians the same right to decide on it as other Australians.”
The Senate has already voted to prioritise the Leyonhjelm bill above all other legislation, putting the government’s signature company tax cuts on hold for now.
But Senator Leyonhjelm said the prime minister, Malcolm Turnbull, promised him a conscience vote in the Lower House as well – and threatened to block other bills unless the vote went ahead.
Last week, Mr Turnbull said a Lower House vote was a “matter the government would consider”.
Senator Leyonhjelm said staff witnessed the deal he says Mr Turnbull agreed to in return for his support for re-establishing the Australian Building and Construction Commission.
"He has a problem with his own party. There are conservatives within his party who basically, they hate the prime minister more than they hate the opposition for reasons best known to themselves," Senator Leyonhjelm told ABC TV on Sunday evening.
"They are looking for every opportunity to give him a hard time. He is very sensitive to that. They are social conservatives so he did not want to give them any ammunition."
Senator Leyonhjelm said he wouldn't give his support for the upcoming legislation, including on industrial relations and a tax on NBN customers,- coming up in the Senate until the deal is kept.
"I am not feeling vindictive about this, I am just annoyed that what was a deal appears no longer to be a deal in the eyes of the government," he said.
"Until they are prepared to accept that's the deal and they stick to the deal... there are 50 or 60 bills waiting in the queue to be dealt with. For me to go either way is pretty easy."
The coalition needs eight of the 10 independent, One Nation and Centre Alliance senators to pass its legislation.
The upper house is expected to debate Senator Leyonhjelm's legislation on Tuesday.
