Ministers are considering how to respond to MPs' decision to reject a European Court of Human Rights (ECHR) ruling that a blanket ban on prisoners voting in the UK is unlawful.
MPs voted overwhelmingly on Thursday to keep the existing ban in place, adding to pressure on ministers on the issue.
A European body has urged the UK to ignore the Commons vote, saying it was "deeply disappointed" by it.
Ministers say they will do the "minimum to comply" with the ECHR ruling.
Cabinet Office officials said they are "considering their next steps" after MPs backed a cross-party motion opposing the Strasbourg court's ruling and urging the final decision on which prisoners should have the right to vote to reside with Parliament.
'Not the end'
Despite its hostility to the move, the government says it has to end the ban on inmates voting, or face being sued for tens of millions of pounds.
Ministers say they will do the "minimum necessary" under European law, having earlier indicated they might restrict the right to vote to inmates serving sentences of four years or less. They have until August to say how they will respond to the court ruling.
Cabinet Office minister Francis Maude said the Parliamentary vote was not "the end of the matter" and government would have to "do something".
"We are going to be obliged by this ruling to vote through - there will be an attempt to vote through - something which most people find repugnant," he told the BBC's Question Time programme.
At present in the UK, only prisoners on remand are allowed to vote.
In 2005, the European Court of Human Rights concluded that blanket ban unlawful, and in June, the Council of Europe, which seeks to uphold its rulings and support human rights and the rule of law, urged the coalition to rectify the situation.
The Council of Europe's Parliamentary body - comprising of delegates from 47 countries - criticised the stance taken by MPs.
"I am deeply disappointed by last night's vote, in defiance of the ruling by the European Court of Human Rights on prisoner voting," said Christos Pourgourides, chair of the body's committee on legal affairs and human rights.
"I had hoped that the parliament of one of Europe's oldest democracies - regarded as playing a leading role in protecting human rights - would have encouraged the United Kingdom to honour its international obligations, as our Assembly urged only last month."
Every member state must implement the judgments of the Court, Mr Pourgourides added.
"The UK government has said that it intends to implement this judgment, and I encourage it to find a way to do so that is consistent with its international legal obligations.
"There are different ways this can be done, as shown by the range of positions on this issue in Council of Europe member states."
Prime Minister David Cameron has said the current situation is "thoroughly unsatisfactory" but the government will have to settle the issue once and for all, while Justice Secretary Ken Clarke has indicated ministers are likely to have to pass legislation in some form.
But during Thursday's debate, a succession of MPs - mainly from the Conservative benches - said enfranchising prisoners was incompatible with their view of justice, would not reduce re-offending and was unacceptable to most of the public.
Senior Tory backbencher David Davis, one of the those who put forward the motion, suggested that he and others would not be satisfied with a mooted compromise allowing those serving terms of less than a year to be given the vote.
Several Labour and Lib Dem MPs have warned that defying the European Convention of Human Rights - to which the UK has been a signatory since its inception - on the issue would have serious consequences.
"My anxiety about this is what 220-odd MPs set out to do was to defy the judgement of a court to whose jurisdiction we have submitted, to breach a treaty obligation," former Lib Dem leader Sir Menzies Campbell told Question Time.
"The strength of the European Convention on Human Rights is that it affects the lives of everyone one of us every day and that is why the Convention should be reaffirmed."