Chief treasury secretary Simon Clarke admitted the Conservatives could U-turn on their opposition to a one-off levy on oil and gas firms to help tackle the cost of living crisis.
Boris Johnson and senior Tories have repeatedly insisted a windfall tax would harm the economy.
Tory MPs voted against the proposed measure in a Westminster vote last week and Mr Clarke said his party were “not philosophically attracted” to the idea.
But Rishi Sunak has recently hinted he would consider the tax on profits, which is broadly popular with the public.
Mr Clarke said: “I think the public are absolutely concerned about the situation they are facing. We’re not ruling it out.
“We’ve always said to the industry that we need to see the industry step up to its part of the bargain and invest in North Sea delivery.
“If that doesn’t happen they are in effect banking the profits and not doing anything to justify those.
“These are effectively one-off and extraordinary gains for the industry.
“We’re not philosophically attracted to this, but if the situation doesn’t improve in terms of them stepping up to the plate we can’t rule it out.”
Labour repeatedly urged the Tories to pursue a windfall tax and say the money can be given to struggling households.
The SNP suggested a one-off levy against other major firms who made huge profits during the Covid pandemic as well.
Some senior Conservative figures have also backed the proposal.
Last week Downing Street was forced to deny they were stopping the treasury from introducing the oil and gas tax.
The prime minister’s spokesman said he had seen reports of division between the departments, but said Mr Johnson and Mr Sunak were “aligned”.
Tory north-east MP Andrew Bowie said: “A windfall tax as envisaged by Labour and the SNP amounts to little more than a raid on the north-east.
“I think the chancellor has been pretty clear his preference is for companies to signal increased investment.
“This isn’t just about multinationals and global profits — I’m really concerned about the tech and supply firms which underpin the local economy, and tens of thousands of jobs across the north east.”