Mystery surrounds a set of nude pictures allegedly taken 30 years ago of the Australian far-right politician Pauline Hanson.

The photographs, published across Australian media at the weekend, purport to show the former One Nation leader partially naked and in skimpy lingerie.

But Ms Hanson says the photographs are not her, and has threatened to bare her belly button to prove it.

Jack Johnson, the "former boyfriend" who sold the pictures to the Sunday Telegraph for A$15,000 (£7,000), admitted today that he could not remember when or where the pictures were taken.

The former army commando also said that he could not remember the surname of the girl he photographed after a drunken night out in Queensland in th 1970s.

He told Australia's Seven Network that he knew "in my heart of hearts" that the girl in the photographs was Ms Hanson.

"But what if I'm wrong?" he asked in an apparent admission that he may have misidentified the woman in the pictures. "I was never the smartest cookie in the barrel."

After declaring through her agent that she "didn't care" about the photographs when they emerged on Sunday, Ms Hanson, who is contesting the Gold Coast seat of Beaudesert in next week's Queensland state elections, spent much of today touring radio and television studios to insist that the pictures were not of her.

She offered to show her navel to compare it with that of the woman in the pictures and, in increasingly indignant denials, she claimed that opposition parties might have set her up.

"I believe a major political party – the whole lot of them – see me as a threat and don't want me there," she told a Sydney radio station. "I'd like to know if they are involved in this,'' she said.

She denied knowing Mr Johnson, and said that at the time he claims to have taken the pictures she was already married with two young children.

"The photographs are not of me," Ms Hanson said. "I am fighting this and I have had enough. This always happens right on election time and it is terribly embarrassing."

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