Cameras were allowed into No 10 for the first meeting of the new cabinet
Prime Minister Gordon Brown will make a statement to MPs on Wednesday about his plans to reform Parliament in the wake of the expenses scandal.
He will unveil plans for an independent body to police MPs' expenses, a legally binding MPs' code of conduct and plans to strengthen Commons committees.
Earlier the new cabinet met for the first time after a week of speculation about Mr Brown's future as leader.
It follows disastrous election results and several resignations by ministers.
Mr Brown is also expected to address the issues of House of Lords Reform and electoral reform in the statement to MPs.
Widespread coverage of the MPs' expenses scandal has been blamed in part for Labour's poor electoral performance - which saw its vote share slip to 15% in the European elections.
Mr Brown has already pledged to end the "gentlemen's club" at Westminster - in which MPs set the rules which govern their own pay and allowances.
BBC political correspondent Carole Walker said Wednesday's announcement must be outline plans - as the whole question of was being looked at by a "national democratic renewal council", which met at Downing Street for the first time on Tuesday.
James Purnell says he hopes to be proved wrong about Gordon Brown
The independent committee for standards in public life is also not due to report back until the autumn, on its proposals to reform MPs' expenses.
Mr Brown's reform proposals form part of a number of policy initiatives as he seeks to reinvigorate his government and move on from questions about his future.
It is expected that a long-promised inquiry into the Iraq war will be brought forward and there may be some concessions on plans to part-privatise the Royal Mail, a policy opposed by many Labour MPs.
Six cabinet ministers have resigned in the past week and there has been open dissent from backbench MPs but Mr Brown appears to have seen off any threat to his position after he addressed a meeting of Labour MPs and peers on Monday night.
Although several MPs told him he should quit, others cheered and banged desks in support of Mr Brown.
Foreign Secretary David Miliband told the BBC: "The Parliamentary Labour Party has reached a settled view about the leadership. The Labour Party does not want a new leader. There is no vacancy. There is no challenger.
Culture Secretary Ben Bradshaw says Brown is in a stronger position now
"The leading candidate Alan Johnson has said he is backing the prime minister to the hilt."
Asked about the surprise resignation of James Purnell as work and pensions secretary on Thursday - in which he called on Gordon Brown to stand aside - Mr Miliband said: "James in the end felt he had a responsibility to resign, I felt we had a responsibility to work inside the government for its renewal."
Meanwhile Mr Purnell has told the BBC he did not regret his "very personal" decision.
"I just knew I couldn't wake up on Friday and say something which I didn't think was the case.
"I said what I said, I stand by it, of course I can be happy if I turn out to be proven wrong and Gordon Brown leads the Labour Party to victory at the next election."
Mr Brown has come under fire for his style of leadership over recent days, including being accused of sidelining the Parliamentary Labour Party.
He can't seem to reshuffle his cabinet but they can't seem to organise a coup
Culture Secretary Ben Bradshaw told the BBC Mr Brown appeared to understand he needed "to behave in a more collegiate way".
"I think he's acknowledged that the way that Number 10 has been operating has not been in the interests of him or the Labour government."
Senior Labour MP John McFall agreed some felt alienated by the "hierarchical" system within the party and there would need to be "much closer engagement".
Environment minister Jane Kennedy resigned from her post on Monday ahead of the meeting, saying she could not support Mr Brown.
During Monday's PLP meeting Charles Clarke, a former home secretary and MPs Fiona McTaggart, Tom Harris and Siobhan McDonagh told Mr Brown he should quit but others said it was overwhelmingly supportive of the prime minister.
Chairman of the Parliamentary Labour Party Tony Lloyd told the BBC: "Gordon Brown is the prime minister, he will lead the Labour Party into the next general election... I can state that as a clear fact. "
But Conservative leader David Cameron said Mr Brown and his critics were locked in "a slow dance of political death".
"He can't seem to reshuffle his cabinet but they can't seem to organise a coup," he said.
A ComRes survey for the Independent suggests Alan Johnson would cut Mr Cameron's advantage if the new home secretary were to become Labour leader.
It said the Tories would lead by 38% to 22% with Mr Brown at Downing Street, but with Mr Johnson at the helm Labour's support would rise to 26% and backing for David Cameron would fall to 36% - enough to deny the Conservatives an overall majority.
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.