Photo: © 2010 AAP/DEAN LEWINS

David Campbell stood down as transport and roads minister last night just before Channel Seven went to air with footage showing him entering and exiting a Sydney gay sex venue.

Journalist Adam Walters has defended his story, saying voters ought to know Campbell has been misleading them over the years.

"He has represented himself [to his electorate] as a family man," Walters told ABC Radio.

"[He even went] to the extent of sending Christmas cards to his constituents highlighting the fact that he is a man of family values."

When asked if he would have made the same decision if Campbell had used a straight brothel, Walters replied it "is a question of integrity and character and deception".

The Sydney Morning Herald's transport writer, Andrew West, has slammed the decision to out Campbell.

He argues that while Campbell had lost focus in his position, "his second life as a gay man had no bearing on his public duties".

"Campbell had never set himself up as a 'family values' campaigner," he writes.

"A photograph of himself with his wife and sons is merely that – a family photograph – not a morals crusade."

Campbell this morning told reporters he has "caused a great deal of embarrassment" and is hoping he can work through personal issues with his family.