From left, Abba's Bjorn Ulvaeus, Agnetha Faltskog, Anni-Frid Lyngstad and Benny Andersson played a smash tour of Australia in 1977. (Associated Press)Australian promoters of AbbaWorld are on the hunt for a missing piece of local memorabilia before the vast multimedia exhibition about the Swedish pop supergroup lands in Melbourne this summer.

Paul Dainty, whose Dainty Consolidated Entertainment is bringing the massive show Down Under, has posted a reward of almost $10,000 for a white jumpsuit that Abba's Agnetha Faltskog wore during the group's 1977 Australian tour.

At the time, Faltskog said Abba had "probably never received such a rapturous reception anywhere. It seemed the ovation would never end" in Australia.

Her coveted concert costume, which bears a purple "A" on the back, was initially given to a flight attendant in 1977. However, according to Australian press, in 2009, the costume was stolen from a shed in Melbourne where it had been stored, and officials believe it was then sold.

Promoter Dainty has said he would like to include the costume among AbbaWorld's extensive collection of stage gear, photos, audio and video programming, memorabilia and interactive exhibits he will mount in Melbourne beginning in June.

"I'm very optimistic we'll be able to find it, because I've got to think that someone in Australia has got this jumpsuit," he told reporters on Sunday.

"I've got to think that someone's got it hidden away and is prepared to get it out for such a good reason."

AbbaWorld opened to international fanfare in London in January and is expected to make its way around the globe.

Abba's Australian tour in 1977 even drew then prime minister Malcolm Fraser, who attended the Melbourne show that March with his wife and daughters. (Central Press/Getty Images)