Labour will force a Commons vote on Monday to call for a planned 3p hike in fuel duty, which is due to come into force in January, to be delayed for a second time.
But Labour's hopes that some campaigning Tory backbenchers would support its motion and rebel against the government looked set to be dashed as Conservatives hinted they had been told the government would reconsider the rise.
Labour is using one of its allotted opposition day debates in the Commons to force the vote, which is non-binding, for a three-month freeze in the face of rising household bills and transport fares as wages remain stagnant.
A number of Conservatives were expected to defy the whip and vote with the opposition to put pressure on the Treasury.
But the Tory MP Robert Halfon, who has led the campaign against increasing fuel duty, said he would not vote against the government until he saw whether the chancellor, George Osborne, responded to the mounting concerns in his autumn statement, due on 5 December.
"The cost of fuel is the No 1 issue, that's why I am campaigning on it," he said. "I have had discussions with various people and it is my view that the government is in strong listening mode. If I didn't believe that, I would make a point and go into the lobby with Labour."
Rachel Reeves, the shadow chief secretary to the Treasury, told ITV Daybreak that a "three-month window" in the fuel duty hike would make a difference to people.
She said that although she was pleased to hear that the government was hinting that it intended to delay the rise, "we haven't heard any confirmation from George Osborne or the Treasury that they will indeed postpone this increase, which is why we are having the vote this evening".
"If the government can find the money to postpone it for longer then all the better because it is a big pressure and of course you've also got bus and train fares going up in January too, so the cost of getting to work for people — there's an issue about whether work pays for a lot of low-paid workers.
"[The consumer campaign organisation] Which? says a lot of people are dipping into savings now … Let's hope that by April next year, the economy starts improving, that the economy is growing, that wages start rising, that inflation starts coming down, because if those things are happening then some of these pressures are more bearable.
"At the moment you've got a situation where wages are not going up but the prices of food, the gas and electricity bills people are going to be getting this winter, the cost of transport, are all going up. When we were in government, we postponed fuel duty increases when the economy was weakened, when families were struggling, and that's what the government should do now."
The campaign group FairFuelUK has said it believes the tax hike could raise only £800m, compared with Treasury projections that it would bring in £1.5bn. It could also cost as many as 35,000 jobs, it said.
The group will be campaigning at parliament before the debate and vote in the Commons.
Its spokesman, the broadcaster Quentin Willson, said: "The momentum building up behind FairFuelUK's call to see this damaging 3p rise scrapped is becoming unstoppable.
"The Treasury appears to be listening. We welcome Labour pushing on this issue. Consumers are currently paying an eye-watering 80p per litre in combined fuel duty and VAT. This is socially unjust and adding another 3p in tax doesn't make sense for economic recovery and deficit reduction."
