Senator Bernardi's office has refused to say who or what organisation has paid for his trip and whether he had sought approval from the Liberal Party to attend.

A spokeswoman could only say she was unable to answer a series of questions put to her by the Herald.

She also declined to respond to questions about whether Senator Bernardi stood by his comments to the Senate on Tuesday, in which he said that legalising gay marriage could lead to demands for polyamory and bestiality to be legal.

On Thursday night, Senator Bernardi told reporters his comments had been reported out of context: ''Ultimately, you do what you think is the right thing.''

Senator Bernardi was forced to quit from his role as Opposition Leader Tony Abbott's parliamentary secretary, and as shadow parliamentary secretary for families, amid outrage at the comments.

But his speech sparked a frosty reception from Britain, even while he was en route.

The British group Conservative Future, which is the youth wing of the Conservative Party, promoted the European Young Conservatives event, but distanced itself from Senator Bernardi.

"We haven't organised this event and are not in control of who attends,'' the chairman Ben Howlett said in an email.

''We strongly condemn Mr Bernardi's comments, which do not reflect David Cameron's or the Conservative Party's viewpoint in any way."

Conservative Future directed queries about the conference to the European Young Conservatives, an umbrella group which says it represents about a dozen conservative, classic liberal and centre-right youth parties in Europe.

Emails to the European Young Conservatives went unanswered.

The Department of Finance and Deregulation said it had not received any request for Senator Bernardi's travel to be paid for by taxpayers.