Camel-riding National MP Richard Worth slipped back into the country yesterday refusing to answer questions about his decision to skip an official commemoration service in Egypt to go sightseeing.

Mr Worth sped past in a taxi outside Whenuapai Air Force Base after returning on an official flight from international and New Zealand commemorations marking the 60th anniversary of the Battle of El Alamein.

The Weekend Herald was stopped from entering the base after Mr Worth told Defence Force staff that he did not want to be interviewed.

The MP for Epsom has been under fire since skipping an official Maori Battalion service and going to Cairo, where, among other things, he visited the Pyramids, went for a camel ride and visited a market.

Prime Minister Helen Clark and Labour MP David Cunliffe were among guests at the service.

Last night Mr Worth's week worsened when he was forced to resign as a director of Prada's America's Cup campaign.

Mr Worth said he was quitting as a director of Prada America's Cup (NZ) Ltd because of suggestions that it was disloyal for an MP to be linked to a challenging syndicate.

He said he became a Prada board member before the last cup, when he was not an MP.

Mr Worth, a former Navy reserve captain and National's defence spokesman, had told reporters in Egypt that going to Cairo was a good decision because it gave him the opportunity of talking to people about defence issues.

He had spoken to a person "very well informed on issues of Muslim extremism".

Shortly after arriving home yesterday, Mr Worth said he had been "so beaten up by the media on this issue" that he would limit his comments to a press release.

In the release, issued by the National Party media unit in Parliament, Mr Worth said he had written to the organisers of the service apologising for any misunderstanding regarding his attendance.

"As a decorated former naval reserve officer, I take these memorial events extremely seriously and would have attended had I received a formal invitation.

"Invitations were issued for the other services I attended, including the Commonwealth, New Zealand and international services.

"The Maori Battalion made a substantial sacrifice in World War II and I honour its warrior tradition.

"It was a privilege to have lunch with a member of the Battalion in the company of the Prime Minister at El Alamein."