Coalition partners Labour and Plaid Cymru have disagreed over moving the 2015 Welsh assembly election to avoid a clash with the UK general election.
Deputy Prime Minister Nick Clegg says he will offer AMs the chance to bring forward or delay the poll up to a year.
First Minister and Welsh Labour leader Carwyn Jones said the UK government should move the general election.
But Deputy First Minister Ieuan Wyn Jones said he welcomed "the opportunity for the assembly to change the date".
A clash in 2015 had looked likely because the UK parliament is moving to five-year fixed terms.
The next general election will be held in May 2015, which will coincide with the assembly election. The assembly currently has four-year fixed terms, and Mr Clegg has also suggested that that could change.
The UK government has now written to assembly Presiding Officer Dafydd Elis Thomas to make the offer.
Two-thirds of AMs would have to vote for a new date.
Mr Clegg said it should be for "the Welsh assembly alone to decide the date of the next election, either a year before that 2015 date or a year later".
But Carwyn Jones, the Welsh Labour leader, said it was up to the UK government to move its planned election in 2015 to avoid a clash with the election to the assembly.
He said: "I'm not persuaded we move our elections.
"My view would be that it's up to the UK government to move its election because at the end of the day our elections were fixed years ago for May 2015.
"I think it's important that those elections are kept on that day. I'm not persuaded at all at the moment that we should move our elections one way or the other."
Ieuan Wyn Jones said he welcomed "the opportunity for the assembly to change the date of the election".
The Plaid leader said: "I have argued that it would not be right that both the UK and the Welsh general elections be held on the same days in 2015.
"It could well be the case that the Welsh public would be asked to vote on representatives in different constituency boundaries using different voting systems which would be both disrespectful and would almost certainly lead to utter chaos at polling stations.
"The Welsh general election is an important opportunity for the people of Wales to have their say on what government they want and should not be overshadowed by other elections."
Mr Clegg said ministers would also consult about the assembly moving permanently to five-year terms to avoid future clashes.