The pledge to complete the reform of the House of Lords could be delayed for at least two years.
The Queen's Speech contained a promise to press ahead with replacing the remaining hereditary peers with a mixture of appointed and elected representatives. A Cabinet Office spokeswoman insisted: "Anything that is in the Queen's Speech is meant for this session."
But Downing Street later made clear that overhauling the second chamber would be a lower priority than its flagship Bills on crime, health and education.
Plans to consult on further reform and the inevitable resistance in the Lords also raise the prospect of the House of Lords Bill being held up until 2003 or beyond.
More than 600 hereditary peers were abolished in the first stage of reform two years ago, leaving 92 hereditaries elected on a temporary basis.
Completing reform of the Lords remains one of the most popular causes with the Labour grass roots after peers inflicted repeated defeats on the first Blair Government.
In yesterday's Queen Speech, the Government committed itself to creating a revamped Lords "better equipped" to work alongside the Commons.
"It would preserve the position of the House of Commons as the cornerstone of our democracy. It would create a second chamber, which is more representative of the people and with a distinctive membership which will look at legislation in a different way from the Commons.
"It would reduce the ability of any government to pack the House with its supporters and would open the way to modernisation of the way the House works."
The Government refused to spell out its preferred model for the revised Lords, saying only that it would build on the recommendations of a Royal Commission headed by the former Conservative minister Lord Wakeham.
Whitehall sources said the Government would publish its detailed plans for the Lords in the autumn. After consultation, the House of Lords Bill would be introduced early next year. They insisted that the aim was for it to receive Royal Assent by the summer of 2002, with the intention of the new-look House sitting by the year 2003.
However, the Prime Minister's official spokesman said: "It's fair to say this is going to be one of the issues that won't be addressed in the first part of the session."
He added: "It's obviously a complex issue. I don't think there is a huge rush."
But Chris Lawrence-Pietroni, deputy director of Charter 88, a constitutional reform group, said: "Following the appallingly low turn-out at the election there could be no more pressing concern than restoring faith in politics and our democratic institutions. The Government has shirked this responsibility entirely."
The Wakeham Commission set out a series of options for a new-look Upper House containing about 550 members.
Ministers are thought to favour his proposal for it to include 87 elected regional members, with the others nominated by an independent Appointments Commission. It would be required to ensure that at least 30 per cent of new members were women and that the ethnic minorities were properly represented.
Government moves to modernise the Lords ran into trouble last month when the first batch of so-called people's peers was widely ridiculed as being élitist. The first 15 chosen included seven knights of the realm and most had already been awarded honours by the Queen.Reuse content