Culture Secretary Tessa Jowell has said Labour MPs have a duty to back the government after the prime minister admitted facing a rough ride on reform.
Mr Blair said he plans to press ahead with his planned reforms
Ms Jowell told the BBC it was time party members got behind Tony Blair on plans to reform schools and hospitals.
Mr Blair has said he faces a tough time but remains determined to press ahead with the government's proposals.
Ms Jowell acknowledged there was a hard core of rebels who may continue to vote against the government.
She told BBC1's Sunday AM programme that the government was re-elected on a manifesto committed to reform and Mr Blair on the "very clear" understanding he would serve for a full third term.
She added: "It is now the duty of the parliamentary party to get behind us and do what people are expecting us to do.
"Every single Labour MP stood on that manifesto and was elected on that manifesto. A manifesto isn't an a la carte menu that you select the bits off that you like."
Ms Jowell acknowledged there were rebels who sought to vote against the government, but insisted that they made up a very small proportion of the parliamentary party.
"I don't believe there's a majority or even a minority of the parliamentary party who want to destroy the great opportunity of a third Labour term, the prospects and hope and opportunity it will bring to millions and millions of people, many of them dispossessed, up and down the country."
Her comments follow Wednesday's rejection of proposals to allow terror suspects to be held for up to 90 days without charge.
The plans were defeated in the Commons by 31 votes, with 49 Labour MPs rebelling against the government.
Ms Jowell accepted it had been "a heck of a week", but insisted the Cabinet was completely united behind Mr Blair.
"What the Cabinet discussion on Thursday reflected with absolute clarity was the solidity and support for what the government is trying to do around the cabinet table.
"There are some people in the parliamentary party who will look for any opportunity to vote against the government and with some of them there is nothing that you can do.
"They have to face, I suspect, the increasing fury of their colleagues in the parliamentary party and the sense of betrayal by the people who elected them."
On Sunday, Mr Blair admitted he faced a "rough ride" but told the News of the World that he and the Cabinet had agreed to "continue doing what is right, not what is easy".
He spoke after MPs backed a compromise proposal to extend the detention time limit for terror suspects from the current 14 days to 28.
Brown said the government and Labour MPs had to unite
Mr Blair described how he had taken "tough decisions" during the government's time in power.
He suggested the government's programme of reforms will target education, hospital waiting times, pensions and welfare benefits.
"All of this will require more difficult decisions and strong leadership....but there is no doubt it will be worth it if, as a result, Britain is better, fairer and stronger."
This week Mr Blair will launch a campaign to gather support for the government's schools White Paper.
On Friday he will campaign on the education plans in the north of England with David Miliband, Alan Milburn and education minister Lord Adonis.
He is also expected to hold a series of meetings with small groups of Labour backbenchers to discuss his plans regarding schools.
Many Labour backbenchers are thought to be unhappy with plans for trust schools, which would be self-governing and independent of local education authorities.
Chancellor Gordon Brown told the Independent on Sunday the government had to "work at it" to get its programme of reforms through Parliament.
He said Labour MPs and the government had a "duty" to work together to avoid future defeats, saying they could not afford to rely on Tory support to push through bills.
"We need to listen to people. We have to listen and learn and talk to people round the country and that is why I am going round the country to listen and visit the regions and listen to what people say," Mr Brown said.
He said it was not the time to discuss "personalities or individuals", which is thought to be a reference to Mr Brown's expected takeover as prime minister.