Fianna Fáil members have passed a motion which "calls on Fianna Fáil, The Republican Party, to organise and contest elections on a 32 county basis".
The motion has come up in previous years but never passed.
But today, after being advocated by Roscommon delegate Mr Denis Ryan, the motion was carried.
Mr Ryan told the conference that the party's goal was the unification of the entire island of Ireland.
All its inhabitants should have the opportunity to play a part in their own rule, he said.
"Yet again we see Northern Ireland being part of the foreign affairs portfolio. Since when has Northern Ireland been a foreign country?" he said.
However, party sources said that there was little chance of members standing for the Northern Ireland Assembly.
The issue will be raised at the National Executive Council and all levels of the party machine, but with Stormont close to collapse it is almost certain the party will not put up candidates, one said.
The Assembly is in crisis following the UUP decision to withdraw members from the Executive, when a motion to have Sinn Fein ministers expelled failed.
Delegates later passed a motion claiming Fianna Fail is the "voice of Irish Republicanism".
Mr Malcolm Byrne, from Wexford, attacked "pseudo-Republicans", saying no true Republican would seek to undermine the Gardaí, fail to condemn punishment beatings or have links with terrorist organisations abroad.
Members carried the motion which read: "This Ard Fheis reaffirms our position as the voice of Irish Republicanism."
PA