David Cameron has urged the MPs' pay regulator to “live in the real world” as it prepares to back a near-£10,000 hike in salaries.
The Prime Minister warned it would be unacceptable for politicians to be treated differently while public sector rises are capped at 1 per cent.
But he declined to say whether he would seek to block a significant rise from the current level of £66,000, insisting he would wait and see what the Independent Parliamentary Standards Authority (Ipsa) recommends.
Ipsa chairman Sir Ian Kennedy used a speech last week to caution party leaders against interfering in the pay setting process.
He insisted failing to tackle the issue now risked a repeat of the expenses scandal, where members fiddled the system to top up their salaries.
Interviewed on ITV's This Morning, Mr Cameron said he hoped the watchdog would "think very carefully".
"I have said very clearly 'look, there is a pay restraint across the public sector, you cannot have one rule for other people and another rule for MPs'," he said.
"So I hope that the independent body will think very carefully before they make their recommendation."
The premier went on: "I have said whatever happens it would be unthinkable for the cost of politics to go up.
"So we have to make sure that we are cutting costs in politics at the same time as they are making whatever recommendation they do make.
"But I hope they will show some understanding that right now when you are asking people in the public sector to restrict their rises as we are you cannot then recommend something different to members of parliament.
"They are independent, it is their decision. But I hope they will live in the real world."
Asked whether he would accept any recommendation for a significant rise, Mr Cameron replied: "We are not at that stage yet. That is very much a conditional issue... Let's wait and see what they say."
Ipsa was given responsibility for pay and pensions after decades of controversy over MPs setting their own salaries and perks.
The body is due to announce its proposed remuneration package on Thursday, with pay expected to rise to around £75,000 but gold-plated pensions curbed.
It will go out for consultation before a final decision is taken in the Autumn, and the new arrangements are due to come into force after the general election in 2015.
The Government has already extended its 1 per cent cap on the rest of the public sector to cover that year.Reuse content