The latest photograph was taken as the Duchess boarded a helicopter to Sydney after an official tour of the Blue Mountains with Prince William last month.
The couple had been visiting Winmalee, a small community where 195 homes were destroyed in the worst bush fires in a decade, as part of a three-week tour Down Under.
As the wind from the helicopter's rotor blades lifted Kate's NZ$580 Diane Von Furstenberg wrap dress, an opportunistic photographer captured the moment and touted it around international newspapers.
It was reportedly sold to the "highest bidder" after British papers refused to print it.
First published in the Bild's Sunday paper, it also appeared on its website, accompanied by crude captions.
Beside the offending picture were the words: "Thank the wind for the insight into the royal household."
"On Sunday, photos appeared which show our favourite Duchess Kate, 32, in the Australian Blue Mountains.
"The royal helicopter rotor blades swirled up the air so that Kate's summer dress began blowing upwards - affording us a glimpse of her beautiful bum.
"Never have we been so thankful to a helicopter for creating such a wind."
The Duke and Duchess of Cambridge have been dragged into a series of privacy rows with the foreign press in recent years after photographs were published of Kate in a bikini while she was pregnant, and topless while on honeymoon.
In February last year, Italian and Australian magazines published photographs of Kate with her bump on display while she walked along a beach on the secluded Caribbean island of Mustique.
And in September 2012, the Duke and Duchess launched legal action for breach of privacy against the publishers of Closer magazine in France after it printed topless photographs of Kate.
A French photographer took the pictures on a long lens from a road, while Kate and William stood on the balcony of a rural chateau in Provence.
Kate and William's lawyer, Aurelien Hamelle, claimed the couple had suffered a "grotesque breach of privacy" and felt "violated" during a "highly intimate moment during a scene of married life".
It is also not the first time Bild newspaper has risked the wrath of the royals.
In 1994, it ran photographs of the Prince of Wales naked on a balcony while on holiday near Avignon, in the south of France.
The images of Charles, with just a white dressing-gown draped over his shoulder, were taken by a French photographer using a long lens. The prince, who was 45 at the time, was described as "hunky like a Greek statue" by Bild.
The Duchess of Cambridge is no stranger to Marilyn Monroe-style wardrobe malfunctions, and had struggled to control the hem of her red dress as she stepped off a plane in windy Wellington, New Zealand, while holding Prince George at the start of their tour last month.
Her navy skirt blew up in the breeze at a charity event in London in November, and she nearly revealed too much in a floral dress as she arrived at Brisbane airport in 2012.
She also narrowly avoided a wardrobe disaster at Calgary airport in September 2011 when her Jenny Packham yellow frock was caught by a sudden gust of wind.
But despite a string of such incidents, Kate has yet to take a leaf out of the Queen's book.
Her Majesty's skirts are always fitted at the hem with small lead curtain weights to prevent the royal hemline from flying away in a gust of wind.
A Kensington Palace spokesman declined to comment on the photograph last night.
- Daily Mail
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