The Ministry of Defense said Adam Werritty was not part of Fox's official party during the trip but acknowledged the two men met in Sri Lanka, The Guardian reported Friday. Fox said he has asked for an investigation to clear up "baseless accusations."
The Guardian said a photograph shows Werritty in the background at a Fox speech in Sri Lanka.
Werritty, 34, and Fox, 50, shared a London flat before Fox's 2005 marriage, for which Werritty was best man.
Fox said this year Werritty has no official position with the Ministry of Defense. But the Guardian said Werritty has given out business cards that describe him as an "adviser to the Rt. Hon. Dr. Liam Fox MP."
Jim Murphy, the Labor Department's shadow defense secretary, said the Sri Lankan trip was questionable in a number of ways.
"We have previously raised serious concerns about his insistence on visiting a Sri Lankan government failing to produce an independent and transparent investigation into allegations of war crimes," Murphy said. "We need a full explanation for his visit as well as clarification of the role of Adam Werritty."