UPDATE 5PM: Malcolm Turnbull has enjoyed a rare win by securing the "strong support" of coalition MPs for his proposed amendments to Labor's emissions trading scheme.

Mr Turnbull was widely tipped to win the support of his colleagues, however, a number of senators voiced their opposition to the scheme as they headed into today's meeting, which started about 3.30pm AEST.

After a meeting that lasted more than four hours on Sunday, coalition MPs and senators supported a set of amendments drafted by opposition resources spokesman Ian Macfarlane.

A Liberal source, who left the meeting before it concluded, confirmed the amendments had won the backing of the party room.

Before the meeting started, Nationals Senate leader Barnaby Joyce and Victorian backbencher Julian McGauran again categorically stated they’d never back legislation for an ETS.

Mr Turnbull walked into the meeting flanked by his deputy Julie Bishop and resources spokesman Ian Macfarlane, who drafted the amendments.

Some members of shadow cabinet offered support for their leader as they walked into the meeting but others remained silent about the issue that has the potential to do serious damage to the coalition.

“I think it’s going to be a very constructive meeting,” senior Liberal frontbencher Nick Minchin said.

South Australia Cory Bernardi, a trenchant critic of the legislation, wouldn’t talk to the media but indicated he’d have something to say after the meeting.

Nationals leader Warren Truss wouldn’t say whether his party would support the amendments.

Queensland National senator Ron Boswell said an ETS would have to be “very different” to win his support.

Liberal frontbencher Helen Coonan said Mr Turnbull’s leadership was “absolutely safe”.

“It’s important we have a good discussion,” she said.

Senior Liberal Andrew Robb, the climate change spokesman who is on sick leave at the moment, said the coalition would be in “good shape” as a result of the meeting.

“The onus is on the government today,” he said.

“The bottom line is if the government scheme as it currently exists was to go into practice it would be a disaster for Australian jobs and it would do nothing for the environment.

“Unless the government adopts in large part what we decide today the country’s got a real problem.”

Mr Robb said he was confident the amendments would win party room support.

But even if the amendments do win broad support, some in the party will never find a compromise ETS bill that would get their backing.

“I will never support an ETS,” Senator McGauran said.

Senator Joyce told reporters he thought the meeting was going to be a “fizzer”.

And he said wouldn’t be supporting an ETS.