Appeal to abandon 10% pay rise to £74,000 for MPs
Downing Street has made a fresh appeal to the body that sets MPs' pay to abandon plans for a £7,000 rise.
It said in a letter to the Independent Parliamentary Standards Authority that the planned rise was "not appropriate".
Ipsa has said unless there is "new and compelling evidence," MPs' pay will rise by 10%, from £67,060 to £74,000.
BBC assistant political editor Norman Smith said PM David Cameron was under pressure after many opposition MPs said they would give the money to charity.
Labour's leadership hopefuls Andy Burnham, Yvette Cooper and Liz Kendall have said they will reject the extra money and Labour leader Harriet Harman is thought likely to do so, our correspondent said.
Education Secretary Nicky Morgan, SNP leader Angus Robertson and Lib Dem leadership hopeful Tim Farron have all said they will give the money to charity.
International Development Secretary Justine Greening said MPs needed to "sort out what is happening" with Ipsa, saying the body is not working.
The letter sent to Ipsa chairman Sir Ian Kennedy by Commons Leader Chris Grayling pointed out that the government had provided a "comprehensive response" to the watchdog's initial consultation on the issue two years ago.
"The government opposed the suggestion that there should be a pay rise of this nature at that time, and the view of the government remains that a pay rise of this nature at this time is not appropriate," it said.
Downing Street had previously indicated that although the prime minister was opposed to the rise, he would accept it.
Appearing on the BBC's Question Time, Ms Greening said the proposed pay rise could not be justified and that she was "incredibly frustrated" and "fed up" with Ipsa.
"Personally I think that we do need to sort out what is happening with Ipsa because how anyone can think that this kind of proposal is acceptable is utterly beyond me."
Education Secretary Mrs Morgan told the BBC is was not the "right time" for a pay rise and said: "I think MPs are going to make it very clear that they don't think this is the right thing to do."
Labour frontbencher Gloria De Piero said the rise proposed by Ipsa was "immoral" and called for the body to give MPs the opportunity not to take the cash.
She said she would give it to charity.
Ipsa's chief executive Marcial Boo said: "Clearly everybody is entitled to their view, but overall MPs are not going to be benefiting any more than they were before because the adjustment to their salary is compensated for by the cuts to their pension and the allowances."
He told the BBC: "MPs, like all of us, are very welcome to choose to give their money to charity when they receive their salary."
Singer Charlotte Church waded in to the debate over MPs' pay, saying the planned 10% rise is "ridiculous".
She questioned in what other industry would salaries be hiked by so much and suggested MPs should "put it back in guys, you'll be alright".
Ipsa was handed control of decisions over MPs' pay and expenses in the wake of the 2009 expenses scandal. It does not need to get the agreement of Parliament to bring in the changes.
Mr Cameron has previously urged Ipsa to scrap the above-inflation increase, which was initially proposed to address complaints that pay had fallen behind the rest of the public sector.
But as it launched its final review of the proposals, Ipsa restated its intention to press ahead with the increase, and said there appeared to be no "material" reason to change the recommendations.