Former London Welsh team manager Mike Scott has been banned from rugby for life for providing false information over the registration of a New Zealand-born halfback.
And the team's been deducted five English rugby Premiership points with a further five-point deduction suspended until the end of next season for fielding ineligible player Tyson Keats - a Christchurch-born former Crusaders and Hurricanes player.
London Welsh were deducted five Premiership points with a further five-point penalty suspended until the end of next season.
The club say they plan to appeal the decision which they say is extremely harsh.
Keats has taken the field in 10 Premiership matches for London Welsh this season without being correctly registered.
London Welsh have also been fined more than $27,000.
The club is now bottom of the table two points behind Sale with five fixtures left.
London Welsh won a court battle to join the Premiership this season.