Nick Clegg has warned that the public would find a bumper pay rise for MPs "impossible to understand" at a time of austerity.
The Deputy Prime Minister also suggested he would forego the increase if it did go ahead following a review by the Commons' expenses watchdog.
The Independent Parliamentary Standards Authority (Ipsa) is thought to be preparing to recommend an increase of £7,500 or 15%, taking salaries to £75,000.
Some MPs insist they should be paid more but any inflation-busting rise at a time of drastic cuts and financial struggle for many Britons would provoke public anger.
Mr Clegg said on Monday: "My own view is that the public would find it impossible to understand, particularly those millions in the public sector whose pay is only increasing by 1%.
David Cameron wants costs to go down"I would certainly seek to do whatever I can to make sure that either this decision is not taken - but that's out of my hands - and if it were to be taken, not to take that pay increase."
His comments came after David Cameron urged restraint and made it clear he wanted the cost of politics to the taxpayer to fall.
Speaking in Asia, the Prime Minister said: "Whatever Ipsa recommends, we can't see the cost of politics or Westminster going up. We should see the cost of Westminster go down.
"Anything would be unthinkable unless the cost of politics was frozen and cut, so I'll wait and see what Ipsa have to say. What I said to Ipsa was that restraint is necessary."
Ipsa is due to announce the findings of a fundamental review into pay and perks later this month, although the main changes will not take effect until after the next general election.
A survey released by the watchdog earlier this year found most MPs wanted to be paid £86,000, although some demanded more than £100,000.
It has been argued that a significant increase is necessary to compensate for the clampdown on second-home expenses and to attract top quality people into Parliament.
Even the smaller rise of £7,500 would take their salaries to almost three times the national average of £26,500 and will spark controversy.
Taxpayers' salaries have risen by just 0.6% on average this year and many are struggling to cope with the rise in the cost of living.
The coalition has also enforced a major squeeze on public sector pay, with salary freezes and new measures in the Spending Review to scrap automatic rises.
In Newcastle, workers told Sky News the rise would be unfair when regular Britons were being hit by pay restraint.
Damian Clark, 38, a teacher, called it "outrageous" and questioned why politicians should not suffer the same pay freezes and cuts as the rest of Britain.
Homa Nelson, a call centre worker for the Department of Work and Pensions, who has seen her pay rises frozen at 1% for the last three years, added that it was "absolutely disgusting".
She accused MPs of "filling their own pockets for nothing" as people elsewhere lost their jobs.
Helen Zato, 54, an East Coast train guard, urged MPs to be "realistic".
"The poor are still suffering and it is not fair for them to have that kind of increment when we work so hard, even harder than them and we don't get it," she said.
Lib Dem minister Jo Swinson told Sky News: "I have no problems whatsoever with my level of pay at the moment.
"I think it is absolutely right that this shouldn't be an issue that is in the hands of MPs to decide. It is something that should be done independently."
Conservative Party chairman Grant Shapps added: "The Conservative Party is absolutely clear.
"We want to see a cut in the cost of politics in this country so I think we will go into the next election saying we want to see the overall cost of politics reduced not increased."
Downing Street has made clear to Ipsa that it expects the "broader fiscal climate" to be taken into account but a spokesman said this did not mean limiting any rise in pay to 1%.
Sources close to Labour have signalled leader Ed Miliband would make MPs accept a 1% pay rise - in line with that for public sector workers - if he won power in 2015.
Downing Street, meanwhile, has made clear it expects the "broader fiscal climate" to be taken into account but a spokesman said this did not mean limiting pay rises to 1%.
"It's more about the general costs in terms of how much politics and doing politics - we're talking about pay, ministers' pay, the number of MPs, all these kind of things - cost the taxpayer," he said.
Ultimately, the Government has little power to block a larger rise because control of MPs' pay was handed to Ipsa after the expenses scandal.
Cabinet Office minister Francis Maude told Sky's Murnaghan programme on Sunday: "MPs' pay is a matter actually not even for Parliament these days.
"It's a matter for the Independent Parliamentary Standards Authority that was set up in the wake of the expenses scandal."
Matthew Sinclair, chief executive of the TaxPayers' Alliance, said: "MPs are already very well paid both in terms of European politicians and the average salary in this country.
"It would be particularly egregious for politicians to be handed a whopping great pay rise while hard-pressed taxpayers tighten their own belts.
"Ipsa must recognise that its own polling shows the public simply do not support an increase, nor would it be consistent for MPs to take a rise while rightly freezing pay elsewhere in the public sector."