The Irish Rugby Football Union has backed plans for South Africa's four Super Rugby sides to join the Pro14, which would become the Pro16.
With South African teams Cheetahs and Southern Kings bowing out of the competition at the end of last season, there are currently only 12 sides competing in the league.
IRFU performance director David Nucifora confirmed that talks are at an advanced stage, and it is hoped an agreement will be reached in the new year.
Nucifora added his belief that the introduction of the Bulls, Stormers, Sharks and Lions would increase the level of competition in the league and in turn would help develop Irish rugby and its players.
"We think that Irish Rugby needs to be ambitious, we think that the Pro14 needs to be ambitious," he said.
"Challenging our teams and challenging our players, and I think that's what high-performing athletes want.
"Sending teams, be it at full strength or teams that are sending down some of the younger players to play and tour in places like Cape Town, Pretoria and Johannesburg, playing full-strength South African sides is something I believe will hold the development of Irish players in good stead for a long period to come."
Exploratory talks to add the four Super Rugby teams began in September after the South African Rugby Union voted in favour of the move.
Three of the four Irish provinces remains undefeated in the current campaign, and the ease with which Leinster, who won every game last season, retained their title has led to questions over the league's competitiveness.
"We don't have the size and playing depth of countries like England and France, so what we do we've got to continue to do well," Nucifora said.
"We've got to expose our players at every opportunity to the highest levels of the game to make sure they're ready to come through when required."