The Labour leader says he will consider a motion of no-confidence in the Government to bring about an immediate general election.
Eamon Gilmore's comments come after the Greens announced they want an election in late January after the Budget has been passed, and negotiations are completed with the EU/IMF.
Independent Jackie Healy Rae has also pulled the plug, saying what he called the "blatant lies" told by the Taoiseach and Ministers means he can no longer support the coalition.
If Labour go ahead with a motion of no-confidence and secure the downfall of the Government, it would result in the Budget's being delayed.