Workers could be clobbered by Rishi Sunak as he considers a £10billion "stealth" tax on wages.
The new Prime Minister is looking at extending a freeze on income tax thresholds, which would leave millions paying hundreds of pounds extra in tax.
As chancellor, Mr Sunak froze the personal allowance, the amount workers can earn without having to pay income tax, at £12,570 for three years until 2026.
The Treasury has now drawn up plans to extend this for an extra two years until 2028, according to The Times.
The impact would be particularly acute as people’s wages rise as inflation soars and the higher rate and additional rate thresholds for top earners would also remain the same.
The Institute for Fiscal Studies forecasts this would raise around £5billion a year.
NFU mutual estimates that extending the freeze by two years would see a worker on £30,000 pay an extra £1,623 in tax.
A Treasury spokesperson told The Mirror: "We do not comment on speculation around tax changes outside of fiscal events".
It comes after the Chancellor Jeremy Hunt delayed a fiscal statement ordered by ex-PM Liz Truss until November 17 amid warnings of austerity cuts.
Mr Hunt said it is "prudent" to delay his fiscal announcement - adding it would be "upgraded to a full autumn statement".
He said he is willing to make "politically embarrassing" choices and insisted a "short two-and-a-half week delay" to his statement is the best course of action.
Mr Hunt told broadcasters: "I've demonstrated in the short time that I've been Chancellor that I'm willing to take decisions very quickly and I'm willing to make choices that are politically embarrassing if they're the right thing to do for the country, if they're in the national interest.
"Now we have a new Prime Minister and the prospect of much longer-term stability for the economy and the country.
"In that context a short two-and-a-half week delay is the best way we will make sure that it is the right decisions we take." we take."
He added: "I want to confirm that it will demonstrate debt falling over the medium term which is really important for people to understand.
"But it's also extremely important that that statement is based on the most accurate possible economic forecasts and forecasts of public finances.
"And for that reason the Prime Minister and I have decided it is prudent to make that statement on November 17 when it will be upgraded to a full autumn statement."