Wales’s World Cup campaign has been thrown into disarray after their assistant coach, Rob Howley, was sent home from the tournament in Japan for suspected betting infringements.

The former Wales captain and scrum-half left Wales’s training camp on Monday to return home to assist with an investigation into a possible breach of World Rugby’s regulation six, which covers anti-corruption and betting. His departure from Kitakyushu comes just a week before Wales face Georgia in Toyota in their World Cup opener leaving Warren Gatland’s preparations for that game on Monday in flux.

Wales, who briefly topped the world rankings in August, had been among the leading contenders for the Webb Ellis Cup but have now suffered the Howley distraction on top of the loss of key players to injury such as the fly-half Gareth Anscombe.

Howley landed back in the United Kingdom on Tuesday afternoon and a subsequent Welsh Rugby Union statement read: “The WRU can confirm that Rob Howley has returned to Wales to assist with an investigation in relation to a potential breach of World Rugby regulation six, 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 cooperated 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.”

Players at all levels as well as agents, match officials, disciplinary personnel, coaching and backroom staff, owners and directors involved at the highest level are banned from betting on any rugby match.

World Rugby’s regulation 6.3.1 states: “No Connected Person shall, directly or indirectly, bet and/or attempt to bet on the outcome or any aspect of any Connected Event and/or receive and/or attempt to receive part or all of the proceeds of any such bet and/or any other benefit in relation to a bet.”

The investigation means Howley has been provisionally suspended from all rugby matters. Should he be found to have committed a breach of the regulations the penalties he could face vary, with the most severe sanction a life suspension from rugby depending upon the nature of the offence.

Howley has worked alongside Gatland, the Wales head coach, since January 2008. The 48-year-old Howley was to leave his role in the Welsh setup after the World Cup and he had been linked with a role with the Italian national side but his future is now under scrutiny.

Howley won 59 caps for Wales and captained his country on 22 occasions in a glittering career that took in playing for Bridgend, Cardiff and Wasps. As a coach he was assistant with the British & Irish Lions on three straight tours in 2009, 2013 and 2017. He has coached Wales on an interim basis on 20 occasions and led the team to the 2013 Six Nations title.

Howley attended Wales’s open training session in the Japanese city of Kitakyushu – where 15,000 locals turned out to watch – on Monday afternoon but he was not present at the team’s official welcome and capping ceremony later that evening as the WRU removed him from the camp.

Gatland and the WRU chief executive, Martyn Phillips, will front a press conference in the early hours of Wednesday UK time to provide more detail on Howley’s departure.

The former Wales and Scarlets fly-half Jones – who was set to succeed Howley as Wales attack coach after the World Cup under the incoming head coach, Wayne Pivac – is on his way to Japan to take over in an emergency role with the full support of Gatland’s senior players.