David Cameron says he has warned Conservative MP Anthony Steen he will be expelled from the Parliamentary party if he steps out of line again.
Mr Steen has apologised for an interview in which he said critics of his expenses claims were simply "jealous" of his country house.
Tory leader Mr Cameron told BBC Radio 4 it was "an appalling thing to say".
He said the Totnes MP - who has said he is standing down at the next election - was on a final warning.
"I gave him a very clear instruction after that interview - one more squeak like that and he will have the whip taken away from him so fast his feet won't touch the ground," Mr Cameron told BBC Radio 4's the World at One.
"It was a completely unacceptable interview. It was a completely unacceptable thing to say. He's announced his retirement from Parliament."
I've got a very, very large house. Some people say it looks like Balmoral
Mr Cameron - who earlier held a public meeting in his Witney constituency to address concerns over the expenses scandal - added that it was "incredibly frustrating when people say things like that".
He added that if Mr Steen said anything like it again "or close to it" he would be kicked out of the Parliamentary party.
The Tory leader was reacting to an interview with Mr Steen that was broadcast on Thursday's World at One, in which he was tackled about Daily Telegraph reports he had claimed more than £87,000 over four years for the home.
Mr Steen, a 69-year-old former barrister claimed ministers had "mucked up the system" by introducing the Freedom of Information Act.
He added: "I've done nothing criminal, that's the most awful thing, and do you know what it's about? Jealousy.
"I've got a very, very large house. Some people say it looks like Balmoral. It's a merchant's house of the 19th century. It's not particularly attractive, it just does me nicely."
However, in a statement on Thursday, he apologised for his comments, saying they were "inappropriate".
Mr Steen said he had been "deeply upset with the situation which resulted in me overreacting".
He said: "I am sorry that in the heat of the moment I said inappropriate things that weren't as measured as I would have liked about the Freedom of Information Act, which I entirely support."
Shadow foreign secretary William Hague described Mr Steen's comments as "ridiculous".
Mr Steen has said he will stand down at the next election. Two other Tories and one Labour MP have said they will do the same.
The warning from Mr Cameron comes as Labour MP Ian Gibson was referred to a party panel to decide whether he should be deselected.
The Daily Telegraph said he claimed for a flat in which his daughter lived rent-free.
Mr Gibson has already said that he is ready to stand down if voters in his Norwich North constituency want him to, although he insists he stuck to the rules.
The Telegraph says Dr Gibson sold the London flat to his daughter and her partner for less than he paid and well below the market value.
He is reported to have sold the flat to them in April for £162,000, despite having bought it for £195,000 in 1999.
Dr Gibson has insisted he acted within the rules and "made nothing on the house whatsoever".
But when asked if he would stand down if constituents wanted that to happen, Dr Gibson replied: "Of course you would do that. It's only your constituents who matter."
He is the fourth MP to be referred to the special panel set up by Labour's ruling National Executive Committee to consider allegations of excessive claims.
'Letter and spirit'
Also published in the Telegraph are financial details of the Tory MP for St Albans, Anne Main.
The paper alleges Mrs Main's daughter has lived at her second home rent-free for up to three years.
Mrs Main told the paper she had done nothing wrong.
Tory MP Peter Luff has also said he believes he kept to the rules, after reportedly claiming £17,000 on home items over four years.
Mr Luff told the newspaper he believed he had acted within the "letter and spirit of the rules" but would repay any money if his judgement was proved to be wrong.
With MPs returning home for the bank holiday weekend - some to face angry constituents - Tory backbencher Nadine Dorries has claimed politicians are the victims of a "witch hunt" and said she feared an MP could commit suicide.
"I think people are seriously beginning to crack," she said.
"There is serious concern that this has almost got to the point now which is almost unbearable for any human being to deal with."
A Conservative Party spokesman said her comments "in no way reflect the views of the party at large".
Sir Peter Viggers - the Tory MP who announced he will stand down at the next election after it was revealed he claimed a £1,645 "duck island" on expenses - refused to speak to reporters who confronted him.
A public meeting is to be held in Bracknell later to decide the future of Conservative MP Andrew MacKay.
He quit as parliamentary aide to David Cameron over what the party said was an "unacceptable" expenses claim.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.