David Cameron is renewing his calls for the organisation that sets pay for MPs to rethink plans for a 10% salary hike.
Downing Street said a letter is being sent to the Independent Parliamentary Standards Authority (Ipsa) underlining the Prime Minister’s opposition to the move.
Mr Cameron has come under pressure to take a stand against the salary increase after the frontrunners in the Labour leadership race made clear they will not pocket the cash.
He previously described the £74,000 proposed pay packet, which comes at a time when the rest of the public sector is restricted to 1%, as “unacceptable” but No 10 indicated earlier this week it would not seek to block the increase.
A Downing Street source said: “We’re writing a letter to Ipsa to reiterate we stand by the detailed submission we had already made to them last year saying we think this rise is wrong.”
The row over the pay deal was triggered after Ipsa launched a final review of the plans, declaring it could see no “material” reason to change them.
Unless a consultation produces “new and compelling evidence” by the end of the month, the move will be confirmed, with the rise backdated to May 8.
The increase was originally unveiled in 2013 to address complaints that MPs’ pay has dropped behind that for other jobs.
Shadow health secretary Andy Burnham, shadow home secretary Yvette Cooper and shadow care minister Liz Kendall have all declared they will forego the rise.
Education Secretary Nicky Morgan said she could increase the amount she gives to charity if the hike goes ahead, and a number of Tories are thought to be planning to donate the benefits. Others MPs are believed to have been asking Ipsa to introduce a mechanism that would allow them to “opt out” of the salary bump.
The document issued by Ipsa stressed that due to cuts in pensions and expenses - such as a ban on claiming for evening meals - the overall package of changes will not cost taxpayers any more.
But MPs elected before 2015 - including Mr Cameron - will see a major boost to their pensions as they are based on final salary.
After trumpeting a “freeze” in ministerial pay last month, Mr Cameron is now in line for an effective 5% bump in his total remuneration, while Cabinet ministers’ overall pay will increase by 5.2%.
Mr Cameron’s total package will therefore rise by 5% this year, from £142,500 to £149,440.