The UK and Irish governments might table their own proposals as a way to break the power-sharing deadlock at Stormont, the Irish PM has said.
Speaking in Washington at an event commemorating the Good Friday Agreement, Leo Varadkar also said efforts to restore Stormont should be redoubled after Easter.
Northern Ireland has been without an executive since January 2017.
Several rounds of talks have failed to restore the power-sharing government.
The Democratic Unionist Party and Sinn Féin remain deadlocked on a range of cultural, social and legacy issues 14 months after their coalition collapsed.
Mr Varadkar said fresh efforts would require very close co-operation and leadership from the British and Irish governments, possibly with Dublin and London tabling their own proposals to help the parties break the stalemate.
"That is how progress was made in the past," said the taoiseach.
"Whether it is done through the auspices of the British-Irish governmental conference or not is not the most important thing."
Analysis: BBC News NI's Shane Harrison in Washington
The cherry blossoms outside the White House are in bloom.
The crowds who gather nearby are still mesmerised by the Trump presidency with all its comings, goings and controversies.
On Thursday, politicians from Dublin, Belfast and London are to visit the White House as part of the week-long St Patrick's Day festivities.
The blossoms will soon wither before eventually returning next year.
After more than 12 months without devolved government in Northern Ireland, the hope for many is that devolution, too, will soon be back in season.
Mr Varadkar added: "The important thing is that the British and Irish governments start to work together to resolve the impasse in Northern Ireland.
"The period after Easter should see a redoubled effort on the part of both governments and all of the parties in Northern Ireland to seek agreement on the restoration of the institutions."
Mr Varadkar said the Good Friday Agreement was a "precious inheritance" and had "evolved to suit new circumstances since 1998, and it will evolve in the future".
'No hidden agenda'
While the remarks may have caught the new Sinn Féin leader sitting in the audience by surprise, Mary Lou McDonald still gave the proposal a positive response.
"We are up for that, we will lead from the front in that regard and we need partners from unionism who equally want that to happen," she said.
SDLP leader Colum Eastwood gave Mr Varadkar's suggestion a cautious welcome.
"If we leave the DUP and Sinn Féin to their own devices we will not have a deal and we have to be realistic about that," he said.
"That's why we need the British government and the Irish government to convene the inter-governmental conference and put a package of legislation through Westminster to get the institutions back up and running.
"That has to happen immediately."
No DUP public representative was present, and former Ulster Unionist leader Mike Nesbitt blamed a lack of trust and poor personal relationships for the current impasse.
He suggested one way forward might be for both sides to agree to past wrong-doing.
"Nobody has clean hands and we are all responsible for where we are today," he added.
Former US President Bill Clinton, speaking via video link, said more needed to be done "to finish the work of the Good Friday Agreement".
Former US senator George Mitchell, who chaired the Good Friday Agreement negotiations, told the event there were 700 days of failure joined by one day of success that changed the course of history.
He called on current politicians to show the same leadership as those of 20 years ago.
Mr Varadkar also apologised to unionists for any offence caused by disagreements over the unfolding Brexit process.
"I want to repeat that we have no hidden agenda," he said.
"My only agenda is the Good Friday Agreement - the principle of consent, peaceful politics, the democratic institutions, reconciliation and co-operation."
Meanwhile, the prime minister has told MPs that her government stands by all its commitments made in December with regard to Northern Ireland and Brexit.
Theresa May also said the UK stands ready to work with the EU and the Republic of Ireland to make sure all those commitments are included in any withdrawal agreement.
"We've been clear that our preferred option is to deliver these through our new partnership with the EU, with specific solutions to address the unique circumstances in Northern Ireland if needed," she said.