World Rugby bosses have hit back at claims 31-man World Cup squads threaten player welfare by insisting that coaches such as Joe Schmidt left their objections too late to have any effect for the 2019 tournament in Japan.

Ireland boss Schmidt has criticised the 31-man World Cup limit, suggesting that is not enough players to attack a global tournament without compromising safety.

World Rugby CEO Brett Gosper said the organisation will review the World Cup squad limits for future tournaments - but insisted coaches like Schmidt needed to raise their concerns far sooner for implementation in Japan.

"The first thing I would say is that we're never entrenched in one particular position; that position has come quite late in the day," said Gosper.

"We believe that there's good player welfare parameters experienced around the size of the squads.

"Coaches generally want more players at their disposal and we understand that. Looking forward we might look at that.

"It does have cost implications but of course, if we do sense and understand that there are real player welfare gains in those squad changes, we would move towards that. So we're not closed to that."

Ireland flew out to Tokyo with existing injury concerns over Joey Carbery and Keith Earls, and have since suffered further scares to key players Rob Kearney and Robbie Henshaw.

Head coach Schmidt would have selected a third scrum-half, a sixth prop and a sixth back-rower had squads been extended to 34 or 35 men as he wanted.

Chief operating officer Alan Gilpin admitted World Rugby will consider raising squad limits for the 2023 tournament in France.

"We've looked at it, we've continued to look at it," said Gilpin.

"Every World Cup throws up some areas for discussion and we'll review that very thoroughly with the teams, team doctors and research after the tournament and move forward into the next cycle planning with the right information.

"I think the way it's been raised so close to this tournament never gave us any opportunity to really look at change for Japan 2019. But we'll definitely review that.

"The move to 31 players actually took place after Rugby World Cup 2011 and particularly in relation to front-row cover."

RTÉ Sport will televise 14 live matches from Rugby World Cup 2019, including all of Ireland's matches, the knockout stages and a daily highlights show. RTÉ Radio will broadcast all Ireland's matches and you can follow the tournament via RTÉ.ie/sport and the News Now app.