Gay marriage hurdle for Queensland's Newman

A Katter's Australian Party commercial intended to paint Liberal National Party (LNP) leader Campbell Newman as a hypocrite for supporting gay marriage has backfired on the minor party.

On Monday afternoon. Liberal National Party leader Campbell Newman abruptly left a media conference, complaining it was going round and around on same-sex marriage.

Reporters were trying to pin Mr Newman down on when a LNP government would repeal the new civil union legislation and if any change would be retrospective, voiding unions already registered.

The issue has returned to the forefront of the election campaign after Katter's Australian Party launched a television commercial questioning whether a vote for Mr Newman is vote for gay marriage.

Watch the ad in full here.

Mr Newman said a LNP government would look at repealing the laws if it didn't leave couples in legal limbo, but didn't firm up a policy.

But he says legislation dealing with what he calls normal Queensland families, such as freezing car registration, will take priority over civil union changes.

The ad asks how well voters know Mr Newman and features him repeating the words: "I support gay marriage."

It also features images of two shirtless men, and Mr Newman handling a skirt.

But instead of achieving its goal, the ad has sparked outrage among Queensland's gay and lesbian community and support groups.

Equal rights campaigner Phil Browne on Monday lodged a complaint with the Advertising Standards Bureau, labelling the ad as "vile".

"The ad uses fear and hate to target homosexuals, an oppressed minority group," Mr Browne said in his complaint.

"This is vile and unacceptable.

"It would be totally unacceptable to use another minority group to promote the same message."

Mr Newman told reporters in Brisbane it was "immaterial" that he supported gay marriage but his party didn't.

He said the priority should be on looking after "normal Queensland families who need their cost of living pressures reduced right down".

But when asked what a "normal family" was, Mr Newman did not exclude same-sex couples from his response.

"(They are) families who are trying to pay their mortgages, trying to make ends meet, who need low vehicle registration costs frozen," he said.

Premier Anna Bligh criticised both the LNP and the party founded by eccentric federal MP Bob Katter.

The ad would not have been made if Mr Newman was clear on whether he would repeal Queensland's same-sex civil union legislation, Ms Bligh said.

"If Mr Newman had given a clear answer on this issue I would suggest it wouldn't be such a big one during the campaign," she told reporters in Brisbane.

"That doesn't excuse Mr Katter's ad though.

"But there's nothing surprising about Mr Katter doing something that's bizarre."

Mr Katter's half-brother Carl Katter, who is gay, is also among the ad's critics.

"This ad ... is totally disrespectful of the many gay Queenslanders who proudly contribute to their state every day of their lives," he said in a statement.

Bob Katter told Network Ten he respected his half-brother's position.

"I admire his candour, his forthrightness in coming forward," he said.