Leo Varadkar has said Ireland cannot agree with a return to direct rule for Northern Ireland in the event of a no-deal Brexit.
The taoiseach (Irish prime minister) was speaking in the Dail on Wednesday.
Mr Varadkar told Boris Johnson when they met in Dublin that he will seek a consultative role for the Republic if direct rule returns.
He said he would do so under the terms of the British-Irish Intergovernmental Conference.
The taoiseach indicated that he and Mr Johnson may meet again next week in New York while they are attending a meeting of the United Nations General Assembly.
Northern Ireland's power-sharing government collapsed in January 2017 amid a bitter row about a green energy scheme.
Mr Varadkar said the chances of restoring devolution largely depend on Brexit.
"If we are able to secure a [Brexit] deal we would be in a good position to do so. If we are not, I think it will be very difficult to do so for lots of reasons," he added.
The taoiseach said Mr Johnson had indicated he might attend the next British-Irish Council (BIC) meeting in Dublin in December.
The BIC deals with matters affecting the two governments, the devolved regions, the Isle of Man and the Channel Islands.
He also indicated that he hoped to meet DUP leader Arlene Foster very soon.
She is due to attend a private dinner of the Dublin Chamber of Commerce on Wednesday evening at which Brexit is certain to be discussed.
There is no media access to the event.
Mr Varadkar also indicated that he and the Scottish first minister, Nicola Sturgeon, agreed to de-escalate tensions over Rockall, a disputed outcrop in the North Atlantic.
But he added that in the event of a no-deal Brexit there would be difficulties over fishing.
He said the EU has proposed that the status quo should continue until the end of the year if the UK leaves the EU without a deal, but that Britain has yet to respond.