Putting an effective cap on power prices is now the key for Malcolm Turnbull to win support in parliament for his national energy plan.
The prime minister got his National Energy Guarantee proposal through the coalition party room on Tuesday, but backbenchers want him to go further to keep prices down.
Having a one-seat majority in parliament means every vote counts.
At least two coalition MPs have promised to vote against it but other sceptics say they can be convinced if there is movement on price.
The guarantee forces emissions to be cut by the Paris-mandated 26 per cent but backbencher George Christensen wants a 17 per cent target.
"If I am being asked to vote for an emissions reduction target based on the Paris agreement, I would have to vote against it," Mr Christensen told The Australian on Thursday.
The Queensland MP joins former prime minister Tony Abbott in promising to vote against the bill.
Senator Eric Abetz also opposes the target but wants to see what the government can do around prices.
"It's too early to say we are absolutely locked in to supporting or opposing," he told Sky News.
Labor quizzed the prime minister over reports one of his ministers Keith Pitt was considering quitting the frontbench in order to vote against the laws.
Mr Turnbull ducked the question, having earlier told reporters no minister had indicated to him their intention to resign.
Labor wants the National Energy Guarantee to have a 45 per cent emissions reduction target and is willing to look at the recommendation from the competition watchdog for a default retail price offer for households and businesses.
Opposition energy spokesman Mark Butler said the Australian Competition and Consumer Commission's idea made sense.
"I think that's a very well thought-out, serious recommendation that we're engaging with stakeholders, with consumer groups," he said.
Bill Shorten's former union, the Australian Workers Union, has joined the CFMEU, farmers, businesses, manufacturers and industry groups in calling for Labor to support the policy.
"Every leading industry group, every large energy user, the experts on the Energy Security Board, all of them are of the same mind that we need to get the National Energy Guarantee established," Mr Turnbull told reporters.
The guarantee is meant to bring power bills down by $550 from 2020.
WA Liberal MP Andrew Hastie is also among those reserving their right to cross the floor.
Others publicly raising concerns include Craig Kelly, Tony Pasin, Barry O'Sullivan, Kevin Andrews and Andrew Gee, while Barnaby Joyce wants to see specific amendments.
Australian Associated Press