The government wants to shift blame for delays in repealing the carbon tax to Labor, as it negotiates with PUP senators on their last-minute amendment.

Senior frontbencher Andrew Robb says the stalled carbon tax repeal is down to Labor, not the Palmer United Party.

The trade minister said the opposition had “welshed” on its election promise to abolish the tax by repeatedly blocking the measure.

The government has been at pains not to blame Clive Palmer for its failed attempt on Thursday to scrap the tax, which was derailed by a last-minute PUP amendment in the Senate.

“The focus need not be, should not be on the crossbenchers,” Mr Robb told Sky News on Sunday.

“The guilty party is the Labor Party. Twenty-five senators last week from the Labor Party voted to not scrap the carbon tax.”

Mr Robb’s comments echo those of Prime Minister Tony Abbott, who told the LNP state conference in Brisbane on Saturday that he expected Mr Palmer to change his mind on the repeal.

“But [Opposition Leader] Bill Shorten will still be there come Monday, come Tuesday, come next week, come next month, come next year, supporting putting your power prices up.”

The government intends to table the repeal for a third time on Monday, confident of amendment negotiations with the PUP that guarantee consumer power bill savings.

Mr Shorten won’t say if Labor will back the PUP amendment, which includes tough penalties for electricity and gas retailers that fail to pass on savings from the tax repeal.

“We’re going to have to see the detail, if it’s indeed a workable amendment from the Palmer people,” he told ABC television.

The government’s attempts to please Clive Palmer may undermine support from other crossbenchers.

Liberal Democrat David Leyonhjelm and Family First senator Bob Day have both expressed concern over “extraordinarily onerous provisions” in the amendment.

Mr Shorten said the two senators had a legitimate concern.

“There’s not much point in repealing a measure if it’s going to cause more compliance headaches than the measure … that you’re actually repealing,” he said.

The Labor leader rejected suggestions the government would call a double dissolution poll over difficulties with the Senate.

“Hell will freeze over before Tony Abbott calls an election based on this unfair budget,” he said.

The prime minister said on Friday it was too soon to talk about an early election, as the new Senate had only been in place for a week.

But he said if the government faced six months or 12 months of difficulty, it might be time “to start thinking along those lines”.