The government's plans are unrealistic, the opposition says
Conservative leader David Cameron has accused the government of a "big omission" by not making any mention of MPs' expenses in the Queen's Speech.
Either ministers were "incompetent" in not realising new laws were needed to implement reforms, or were afraid of Labour backbenchers, he said.
Sir Christopher Kelly, author of the reforms, said he was "disappointed".
But he later said he had been reassured by the government that the necessary new laws would be put in place.
Sir Christopher's committee on standards in public life carried out a six-month inquiry in the wake of the scandal about MPs' expenses and made a series of recommendations earlier this month to change the system.
While he was conducting his review the government rushed through legislation to set up a new body, the Independent Parliamentary Standards Authority, with the power to implement the Kelly review's recommendations.
But Sir Christopher said in his report that the new authority did not have sufficient powers and should be made responsible for MPs' pay and pensions, as well as expenses, and be given tougher enforcement and investigation powers, among other changes.
In a statement issued after the Queen's Speech, he said: "It is disappointing therefore that today's Queen's Speech did not contain measures to address the changes we believe to be necessary affecting the remit, powers and independence of the new body being established to regulate expenses."
But in a later statement, he said: "This is too important an issue to play party politics with. The government has clarified its position on legislation to reform MPs' expenses.
"If, as I understand it, this means that necessary legislation will be in place before the start of the next Parliament, I very much welcome that. It is important that the new Parliament starts with a clean sheet."
'Fear of backbenchers'
Mr Cameron said there were 11 measures which needed to be passed into law in order to implement the Kelly report - but accused Mr Brown of "a great big silence" when challenged to bring them forward.
He told BBC Radio 4's Today programme leaving expenses out of the speech was a "big omission".
"Either the government is incompetent and hadn't realised that Kelly's report requires these laws to be passed or they are frightened of their own backbenchers, or perhaps they don't think cleaning up the House of Commons is as important as they said it was."
Liberal Democrat leader Nick Clegg also said new legislation was needed, specifically to force MPs to disclose their financial interests.
Number 10 has said the prime minister was ready to bring forward any legislation needed to complete his reforms "on a cross-party basis as required".
Commons leader Harriet Harman told the BBC: "I think that the things Sir Christopher has recommended can and will be taken forward by the Independent Parliamentary Standards Authority.
"I don't want anyone to think that we have simply not taken the action that was necessary."
Some recommendations, like the proposed ban on employing relatives, did not require legislation she said, adding she would be "happy to discuss" those that did.
She accused Mr Cameron of creating a "smokescreen" adding: "It's not true to say that loose ends have been left and we are somehow half-hearted about this."
But she said: "I will need to reassure Sir Christopher that the things that he wants done, will be done, those legal changes that he doesn't agree with can simply be dealt with by not bringing them into effect."
She told MPs: "We are going to make sure that these reforms are all taken through."
However she faced Conservative accusations in the Commons that the government's position was "mired in confusion" and that it had been "caught napping".
'Waste of time'
Labour is widely regarded to have used the Queen's Speech, unveiled amid typical pageantry at Westminster, to draw the battle lines for the upcoming election, which must be held by next June.
Among the 13 bills announced were measures to penalise excessive risk taking in the City, to provide new pupil entitlements, to give free personal care to about 400,000 pensioners and to require the government to halve the budget deficit in the next Parliament.
Ministers denied the proposals amounted to a virtual election manifesto, saying they were putting national interests ahead of party interests.
But the Tories said the paucity of proposals showed Labour had run out of "money, time and ideas".
The Lib Dems labelled Labour's agenda a "fantasy" and said it was a "waste of time" as half of the proposals would never make it into law.