The coalition government is under fresh pressure to allow some prisoners in the UK the right to vote.
The Council of Europe has asked the UK to come up with changes within three months, after five years of stalling.
But the Conservatives and Liberal Democrats hold opposing views on the issue and ministers will not comment "until the approach is settled".
The former Labour government said some prisoners would get the vote - but did not legislate before losing power.
The Council of Europe is an inter-governmental organisation that oversees and enforces rulings made by the European Court of Human Rights.
At a meeting last week, the Committee of Ministers at the council "expressed profound regret" that the UK general election had taken place without any changes to the "blanket ban" on prisoners voting.
But in a statement, it "expressed confidence that the new United Kingdom government will adopt general measures to implement the judgement ahead of elections scheduled for 2011 in Scotland, Wales and Northern Ireland".
The committee said it would issue a resolution in September if the matter was not resolved.
The row over prisoners voting in the UK has dragged on since 2005 after the European Court of Human Rights said that the UK's blanket ban was unlawful.
The former Labour government admitted said some reforms were "unavoidable" but did not put proposals before Parliament, despite threats of further legal action.
In April 2009, the Conservative's Dominic Grieve, now Attorney General, said that it was "perfectly rational" that jailed criminals should be denied the vote.
But the Liberal Democrats said it should be up to judges to decide which criminals are disenfranchised on entering jail.
The coalition's policy is unclear - and the issue is not on the public list of constitutional matters being dealt with by Deputy Prime Minister Nick Clegg.
In a statement issued via the Ministry of Justice, a coalition government spokesman said: "Until the approach is settled, it would not be appropriate to comment further."
John Hirst, the former prisoner who challenged the ban in Europe, told the BBC: "The council of Europe threatened the UK to grant the vote before the general election or else. We have come down to 'or else'.
"The government needs to grapple with this and be honest with the public about what they are going to do. They don't want to get into the same bind as Labour."