Commons authorities are fighting the ruling at the High Court
Several MPs have raised concerns about the Commons authorities' decision to fight in court a ruling that details of 14 MPs' expenses must be published.
The Commons says part of the ruling - that MPs' addresses be published - could compromise MPs' security.
Among the 14 is Lib Dem Mark Oaten who said he had not been consulted yet was getting "all the flak this morning".
The prime minister's spokesman said he was "relaxed" about expenses being published but it was up to the Commons.
The Commons authorities had until Tuesday to release a detailed breakdown of 14 MPs' claims under the Additional Costs Allowance (ACA) - the expenses associated with running a second home.
But instead it decided to launch a last-ditch appeal to the High Court - arguing that if MPs' addresses were published, it could compromise their security.
It has led to criticism that public money is being used to block the public's right to know.
At prime minister's questions, Labour MP David Winnick raised a point of order asking about the specific grounds for appeal.
He said if it was just about publishing addresses "that would be perfectly understandable on grounds of security".
But he said if it was against the wider issue of publishing second home expenses, "it should be noted that some members, certainly myself, are very much opposed to the appeal being lodged".
He said it was "unfortunate" they had not been given a vote on the matter.
Grounds for appeal
He was interrupted by Speaker Michael Martin who said: "This matter is before the court and therefore it is sub-judice for the House of Commons.
"I know that the media can talk about it but for the House of Commons the rules are quite clear."
He said Mr Winnick could go and find out the grounds for the appeal himself from the High Court.
The Liberal Democrats have urged the Speaker to publish all details, except the addresses, as soon as possible.
A spokeswoman for the party's leader Nick Clegg said: "We agree with the appeal about the publication of addresses. But that doesn't mean that the rest of the expenses cannot be published now."
Two journalists and a Freedom of Information campaigner have been fighting since 2005 to get the details published.
The list of 14 MPs includes Prime Minister Gordon Brown, his predecessor Tony Blair, Tory leader David Cameron and former Lib Dem leader Sir Menzies Campbell.
On Wednesday, the prime minister's official spokesman said Mr Brown was "completely relaxed" about the possibility of his ACA claims being published.
He said any decision to publish the details was a matter for the Commons Members Estimate Committee: "If the House authorities decide to publish expenses, including his, then he would be entirely happy."
Mr Oaten, who is also on the list, told the BBC earlier he had not been asked whether he wanted to appeal against the ruling.
"It does appear that the MPs involved, the 14 MPs involved, weren't consulted about this decision but we are getting all the flak this morning, as if we are trying to hide something.
"So my judgement is, probably we should just have accepted this and made public this information."
Senior Labour MP Frank Field said the list included some "very senior people".
He said: "I think it's folly to make it easier for people to attack, physically attack people in public life.
"But we again look... we look as though we are on the back foot rather than on the front foot."