The heat is on Labor to back the Turnbull government's national energy plan as indications point to opposition MPs' votes making or breaking the policy.
The party is saying it will work constructively with the government on its National Energy Guarantee but has declared Australia can't lock in emissions targets that have "almost no ambition".
Malcolm Turnbull got his energy proposal through the coalition party room on Tuesday, despite resistance from a small group of MPs.
But the guarantee is now likely to need Labor's support to pass parliament if a number of coalition MPs choose to vote against it.
Bill Shorten's former union the Australian Workers Union has joined the CFMMEU in calling on the party to support the policy employers are "screaming" for.
Prime Minister Malcolm Turnbull also piled the pressure on Mr Shorten on Thursday morning.
"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 to bring down electricity prices by $550 per average family household over the period from 2020," he told reporters in Canberra.
"There's a lot at play here and the time has come for Bill Shorten to say he stands for lower electricity prices."
Senior Labor frontbencher Tony Burke said the opposition would work constructively on the energy policy, but added that a 26 per cent emissions target was inadequate.
"The challenge that we've got is to make sure that a lack of ambition is not permanently locked in," Mr Burke told Sky News on Thursday.
"We want there to be a framework, and we want there to be a proper level of ambition. The ball's in the government's court to produce legislation."
To win over the disgruntled coalition MPs, the government is considering putting in a place a "default deal", which would effectively put in place a price cap for customers while ensuring retails could still make a profit.
Treasurer Scott Morrison said he and other ministers were working through the issues "respectfully with colleagues".
Former prime minister Tony Abbott, George Christensen and Andrew Hastie have reserved their right to cross the floor.
Others publicly raising issues include Craig Kelly, Tony Pasin, Eric Abetz, Barry O'Sullivan, Kevin Andrews and Andrew Gee, while Barnaby Joyce has signalled specific amendments he wants to see.
Coalition MP Keith Pitt is also reportedly considering resigning from the frontbench in protest over the NEG.
But Mr Turnbull said no minister had indicated plans to resign, while Mr Morrison described talk of a frontbench walkout as "overly dramatised".
