WELLINGTON New Zealand Rugby (NZR) launched an independent inquiry Tuesday into allegations Crusaders players engaged in homophobic abuse and groped a woman during their recent trip to South Africa.

NZR chief rugby officer Nigel Cass described the allegations as "very serious" and said a lawyer had been engaged to investigate them.

"These allegations are about abuse, inappropriate and offensive behaviour, and we do not tolerate this," he said, noting that the players involved strongly disputed the claims.

One incident allegedly involved a group linked to the Crusaders  including at least one player  making homophobic and threatening remarks at a Cape Town fast food restaurant late Saturday after the Super Rugby side's 19-19 draw with the Western Stormers.

The other reportedly took place a week earlier in the same city, when another player is accused of spitting beer on a woman in a bar then pinching her bottom.

Media reports in New Zealand named the player in the bar as fly-half Richie Mo'unga, while Crusaders coach Scott Robertson told reporters that wing George Bridge was one of those in the restaurant.

Robertson told reporters the incident was "a selfie gone wrong" and Bridge was insistent there was no homophobic behaviour.

Mo'unga, 24, has played nine Tests and is widely tipped to be part of the All Blacks' World Cup squad as back up to Beauden Barrett.

Bridge, 23, is a fringe international who has played one Test, against Japan last year.

Crusaders chief executive Colin Mansbridge, who on Monday expressed confidence there had been no wrongdoing, said the players were distraught.

Cass said the accusations would be investigated "without prejudice or assumptions", with all involved, including alleged victims, asked to give their versions of events.

He said the investigation would be finished as soon as possible. 

The sport's attitude towards gay people is under the spotlight after Rugby Australia sacked star Wallabies Israel Folau over homophobic social media posts.

AFP