Rugby union's governing body decided on Thursday night not to accept a ruling by the Canadian Centre for Ethics in Sport to clear Commonwealth Games sevens player Fred Asselin of a possible doping offence.

The IRB's anti-doping advisory committee chose not to accept the CCES decision which they were informed of by Rugby Canada.

They will make a definitive decision on Friday, with Canada due to face New Zealand at 6:20pm and Asselin on his way to Manchester.

Asselin was earlier today cleared by CCES of any wrongdoing after it was revealed on Monday that he had taken painkillers for toothache which contained a banned substance.

The 10-time capped Canadian Test player was told by the CCES, an independent body, that no further action need be taken.

An IRB statement said: "The IRB anti-doping advisory committee on behalf of the IRB has undertaken a preliminary review of the case referred to it by Rugby Canada.

"The anti-doping advisory committee did not accept the result as communicated to it by Rugby Canada and has decided to refer the matter to an IRB appeal committee for further consideration.

"The IRB's appeal committee will consider the case prior to the commencement of the tournament."

The new chief executive of Rugby Canada, former international fly-half Gareth Rees, revealed how it was during the course of routine pre-Games testing that Asselin admitted he might have taken a banned substance.

A morning statement from Rugby Canada revealed: "No further action shall be taken with regard to determination of whether Fred Asselin committed a doping-related infraction.

"The athlete has therefore been cleared to compete and is in good standing with the CCES."

However, Rugby Canada knew they still had the IRB hurdle to clear before the British Columbia winger could lace up his boots for action in Manchester.

It was by no means a given thing that Asselin would be permitted to play, and the Canadians will now have to prepare knowing there is a fair chance he will not be involved.

The Asselin controversy came as a second blow to the Canadian Commonwealth Games team who had to cope with triathlete Kelly Guest testing positive for nandrolone.

Canada reached the rugby sevens quarter-finals of the 1998 Commonwealth Games in Malaysia.

If the IRB reject the request from Rugby Canada to lift the suspension, Asselin's international career could be in jeopardy.

The winger was named in the senior squad for upcoming matches against Uruguay and Chile in the next round of Americas Zone qualifying for the 2003 Rugby World Cup in Australia.