Controversy over Murdoch's invisible crow's feet

Sarah Murdoch has been forced to defend a series of promotional shots for Australia's Next Top Model that show her wrinkle-free and with a shrunken waist.

Murdoch, who hosts the Fox8 reality show, was applauded after featuring on the cover of Australian Women's Weekly in October last year without any digital touch-ups.

The mum-of-three said at the time she believed magazines should embrace the ageing process and that she did not like seeing airbrushed images of herself.

But in a set of publicity shots for Next Top Model, which began its sixth season last week, Murdoch's face is heavily retouched.

The 38-year-old's already svelte body also appears to have been slimmed down even more.

Murdoch, who recently gave advice to Youth Minister Kate Ellis on healthy body image issues, released a statement defending the photos, saying she had never ruled out ever appearing in a retouched photo again.

"[Sarah's] appearance on the cover of the Australian Women's Weekly unretouched was and remains an incredibly bold and important statement," the statement, published in The Sydney Morning Herald, said.

''Sarah will, of course, continue to appear in both completely natural campaigns as well as photos that require hair, make-up and retouching to suit a client's needs, as you would expect from any professional."

Body image expert and social commentator Melinda Tankard Reist slammed the photographs, saying Murdoch was sending contradictory messages to young people.

"You can't sit on a body image advisory board that is critical of airbrushing practices, which says these practices must be disclosed and then allow yourself to be featured in touched-up photographs," Ms Reist said.

"The latest Next Top Model ads show women looking out of horse racing stalls and they're depicted as greyhounds chasing bait ... is this a healthy depiction of women?

"You either want be a serious advocate or you don't — you can't have a foot in both camps."

Ms Reist said a group of body image professionals were preparing to send an open letter to Murdoch, asking why she has put "her good name" alongside Next Top Model.