World Rugby says it "fully supports" the Welsh Rugby Union's "proactive approach" over the Rob Howley affair.
Howley was sent home from the World Cup in Japan for an alleged breach of World Rugby's betting and anti-corruption regulations.
The WRU said that Howley had "returned to Wales to assist with an investigation in relation to a potential breach of World Rugby regulation 6, specifically betting on rugby union".
"World Rugby has been informed by the Welsh Rugby Union of a potential breach of World Rugby Regulation 6 (specifically betting on rugby) by a member of the union's RWC 2019 coaching team.
"World Rugby fully supports the WRU's proactive approach to this matter and can confirm that the union is keeping us informed of their initial discussions.
"It would be inappropriate to comment further on an open and evolving process," the organisation said.
The 48-year-old former Wales captain has been part of Warren Gatland's coaching team since 2008.
Howley is already back in Britain after leaving Wales's current World Cup squad base in the southern Japanese city of Kitakyushu.
Former Wales fly-half Stephen Jones, who was due to succeed Howley as attack specialist after the tournament, will join the squad before next Monday's World Cup opener against Georgia in Toyota City.
In a statement issued on Tuesday, the WRU said it "can confirm that Rob Howley has returned to Wales to assist with an investigation in relation to a potential breach of World Rugby regulation 6, specifically betting on rugby union.
"The decision was taken to act immediately in light of recent information passed to the WRU.
"No further details can be provided at this stage as this would prejudice the investigation. If required, an independent panel will be appointed to hear the case.
"Rob has co-operated fully with our initial discussions, and we would ask that the media appreciate this is a difficult and personal matter for Rob and that his privacy is respected before an outcome is reached.
"Warren Gatland has consulted with senior players, and Stephen Jones will be arriving in Japan imminently to link up with the squad as attack coach."
If found guilty, Howley could face the maximum sanction of a life ban from the sport.
Betting on any rugby game is outlawed for the likes of players, coaches and match officials, among others.
Howley is provisionally suspended from any rugby-related activity, pending an investigation.
