The Referendum Commission has said the only way the vote on the fiscal treaty on May 31 could now be called off is in the event of a General Election being called.
The Commission has this afternoon issued a statement which follows repeated calls on the coalition to delay ratification of the treaty.
According to the Commission, the Referendum Act 1994 clearly states that once the date is set it cannot be changed, except if an election is called, and then only to the same date as that election.
Responding to the Commission's statement, Libertas founder and No vote campaigner Declan Ganley said: “If the Government cannot or will not postpone this referendum, it is up to the people to do so by voting no on May 31.
"It makes no sense for Ireland to accept this deal as it currently stands when we have an opportunity to seek a deal that is focused on tackling the real problems like bank debt which can be put to us later this year," Mr Ganley said.
"This decision must be put back until all our options are much clearer, and by doing so we also get the opportunity to make a real deal on bank debt, and vote on a treaty that offers stable growth, not stable stagnation."