The IRFU and the FAI may team up to build a new 60,000-seat stadium in Dublin, officials said today.
The IRFU said it was in talks with the FAI about jointly funding the new venue, at an estimated cost of around €250 million.
However, the project would require government assistance of around €150 million, an IRFU spokesman said.
"The IRFU feel the need for a stadium and they need support for this, and while the FAI would be a ready-made bedfellow, the kernel of the thing is that they will need government money," the spokesman said.
He said the two sports bodies - due to meet for further talks in January - could raise around #8364;100 million, partly by pre-selling 10-year ticketing.
Ireland's lack of sports stadiums was seen as a key factor in the failure of the country's joint bid with Scotland to host the Euro 2008 soccer championship earlier this month.
The IRFU spokesman said a redevelopment of Lansdowne Road had not been ruled out and was among a number of options under consideration.
"It's a question of all the parties getting together to identify the site and then pushing the project forward."