MARTIN McGuinness wants a referendum on a united Ireland as early as 2016 but the DUP has moved to pour cold water on his proposals.
The Sinn Fein chief mooted the prospect of a referendum coinciding with one of the key dates in the republican calendar - the centenary of the Easter Rising.
"It just seems to me to be a sensible timing," he said.
"It would be on the question of whether or not the people of the six counties wish to retain the link with what is described as the United Kingdom or be part of a united Ireland.
"It could take place anytime between 2016 or 2020 to 2021.
"I don't see any reason whatsoever why that should not be considered.
"I think, in all probability, the people who have got the power to put that in place won't even contemplate it this side of the next assembly elections, which conceivably could be 2015 or 2016."
Under the Good Friday Agreement, the power lies with Britain's secretary of state Owen Paterson to decide when any referendum should be held.
Mr McGuinness told the Irish Examiner he believed the DUP would be persuaded to hold a referendum.
However, the DUP's chief whip Peter Weir said the prospect of a referendum was "unrealistic".
"We take no satisfaction from the economic turmoil being suffered by our neighbours in the Republic of Ireland but we do recognise that such conditions has put paid to any idea that it would be beneficial for us to leave the Union," Mr Weir, pictured, said.
"I am confident that in 2021 Northern Ireland will celebrate its 100th anniversary as a state and will be setting ambitious plans for our next 100 years."