Ministers have defended their expenses claims saying all were made within the rules, as police are asked to probe how the details were leaked to a newspaper.
Downing Street says there was "nothing wrong" with Gordon Brown's £6,500 claim to pay his brother for a cleaner.
Lord Mandelson, who claimed £2,850 for his home, before quitting as an MP and selling it for a large profit, said the claims were for essential repairs.
The Telegraph published the details and says other parties' claims will follow.
But some ministers are annoyed that details had been leaked, before they were due to be published in July, and have claimed that it was a politically motivated story by a Conservative-supporting newspaper.
System 'doesn't work'
The BBC's political editor Nick Robinson said it did not appear any one allegation would be enough for a minister to lose their jobs - but an impression had been created that, at best, MPs were casual about claims and at worst, were deliberately trying to get every penny from the system.
The Commons authorities have made a complaint to the Metropolitan Police, who have confirmed they are considering a request to launch an investigation into the leak.
And the BBC understands House of Commons Commission, a supervisory body chaired by Speaker Michael Martin, will meet on Monday to decide whether to release the details of all MPs' claims early.
In a separate development police have also confirmed that they have received a complaint about work minister Tony McNulty's expenses claims.
He has said his second homes claim - for a property in which his parents live, eight miles from his main home - was within the rules and said he had made "considerable" use of the property.
Scotland Yard confirmed it was considering a complaint that Mr McNulty may have "obtained pecuniary advantage by deception".
Gordon Brown, who is in Bradford for a memorial ceremony, has said a "better system" for expenses is needed - but one that recognises that MPs must live in two places, Westminster and their constituency.
"The system doesn't work," he told the BBC. "I've said it doesn't work, it's got to be changed. We voted for change and that change has got to come quickly."
His spokesman said any suggestion there was something wrong in the arrangement whereby Mr Brown paid his brother for a cleaner they both shared was "wholly unjustified".
The Telegraph revelations include Communities Secretary Hazel Blears claiming three different properties within a year were her "second home" - the first in her Salford constituency, the second two in London. MPs can claim up to £24,000 a year towards the costs of their second home.
'In good faith'
Ms Blears said the claims were "entirely in accordance with the rules" adding: "I have only ever had one small, one-bedroom flat at any time in London."
Justice Secretary Jack Straw said he had repaid £1,500 which he claimed to cover the full rate of council tax on his constituency home - when he was getting a 50% discount. He told the BBC he had acted "in complete good faith and within the rules" but regretted the "error" on council tax.
What I don't want to see is for people to feel that all MPs are corrupt and the system is rotten because I don't believe that to be the case
But asked how his colleague - Environment Secretary Hilary Benn - apparently managed to claim only £140 for the whole year under the allowance, Mr Straw added: "I will talk to Hilary about how he manages it."
Lord Mandelson said the Daily Telegraph report created "the perception of wrongdoing" about his claims for his constituency home - lodged after he said he would be standing down as an MP.
He reportedly went on to sell the property for a £136,000 profit but denied he had claimed to improve the house - he said the claims were to repair a roof which was letting in water.
The Telegraph has not confirmed if it paid for the details but says it was in the public interest to publish them and they will be publishing details of other parties' claims.
The newspaper also says the Commons authorities had planned to blank out the addresses of MPs, potentially concealing the way some had regularly changed homes in order to maximise their income.
Its chief political commentator Benedict Brogan said: "For the first time after years of trying to get this information, Telegraph readers and the general public will have an idea of the systemic abuse of parliamentary allowances that has been going on for years and has grown up out of a system that clearly is no longer suitable for what it's designed to do."
Liberal Democrat leader Nick Clegg told BBC News the issue "affects all politicians of all parties".
Repeating his call to stop MPs buying properties using public money, he said: "I think people will just simply despair that all politicians look either ridiculous at best or corrupt at worst."
Conservative leader David Cameron said: "I completely understand how angry the public are about this and we desperately need change.
"I have argued for a long time that we've got to cut the cost of the expenses regime ... we've got to radically reduce the number of things that MPs can claim for and we've got to sort out the system."
David Cameron says people are 'rightly angry' about MPs expenses
He said every MP had to explain their claims themselves. "That's what I will do when mine are published and I look forward to that happening," he added.
More than 2 million receipts to back up claims made by all MPs since 2004 are being digitised and edited ahead of their publication in July.
The Commons authorities fought and lost a High Court battle last year to prevent their publication under the Freedom of Information Act.
Last week MPs voted through some changes to the second homes allowances including making all claims require a receipt and stopping MPs representing greater London constituencies from claiming it.
But more widespread reform has been left to Sir Christopher Kelly's independent committee on standards in public life - which is carrying out a review and is expected to report back by the end of the year.
A ROUND-UP OF OPINION ON THE EXPENSES LEAK
Newspapers and blogs are not short of comment about, analysis of and reaction to the MPs' expenses figures published in
. Most despair at some of the receipts submitted by the Cabinet before anticipating what's coming next.
The other parties are not innocent, however. The Telegraph says MPs from all parties are implicated by their expenses exclusive. We all paid £1,775 for Farrow and Ball paint for the renovation of a Tory shadow minister's country home, for example. One wealthy Tory MP charged £10 for a bag of manure. [Mild scatological wordplay deleted]
At the Spectator's Coffee House,
James Forsyth is more sanguine about the likely effect on the Conservatives
, on the basis that there are "only three members of the shadow Cabinet who have anything approaching national name recognition: Cameron, Hague and Osborne. Labour, by virtue of being in government for more than a decade, has far more politicians who the country [is] aware of":
As long as the Tories the country knows haven't made any outrageous claims then this story will hurt Labour more than it does the Tories.
Led a merry dance by his fragrant nemesis Joanna Lumley, now the saviour of the world economy stoops to publishing his cleaner's contract. Airing his clean washing in public. Too much information, surely?
[O]ne of the most interesting pieces in the Telegraph today
argues that without [MPs'] addresses, the newspaper would not have been able to shed light on some of the questionable practices it reveals. So some of today's revelations may be as much as about leaking, or "chequebook journalism", as about freedom of information.
At the one-stop shop for those who like a punt on matters ministerial, Political Betting,
Mike Smithson cheers "an amazing period for political news"
and asks the big question - big, that is, if you're thinking of gambling on the identity of the next Labour leader:
So what are the betting implications of all of this? Is it good news for Alan Johnson backers?
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