Wales were warned by World Rugby for having non-squad player train against them yesterday.
The investigation comes after reports that players on stand-by, who are nor part of the official 31-man squad, trained in Sunbury yesterday.
Many players, Nicky Smith, Rob Evans, Rhys Patchell, Jordan Williams, Dan Baker, Kristian Dacey, Dan Fish and Aled Summerhill, were involved in training, with is against World Cup regulations but head coach Warren Gatland was adamant they haven’t broken the rules.
He said: “We haven’t broken any rules. Apparently we have broken the ‘spirit of the rules.
“What that means we don’t know. I don’t know what we have done wrong.”
Meanwhile a World Rugby statement read: “All participating teams have been informed that additional players from the extended squad, including potential injury replacements, may not be included in any training sessions.”