Dokic has been well suported on her return to Australia this month

Damir Dokic, renowned for his erratic behaviour, is quoted in Serbian daily Kurir as saying he has "thought about dropping a nuclear bomb on Sydney".

Damir said he sought help from Serbian politicians in kidnapping Jelena.

He added: "I have even thought about killing an Australian in revenge, but I wouldn't gain anything from it."

Jelena responded in a statement: "This has proven to be yet another unfortunate distraction around my return to Australia and competitive tennis.

"I have spent my life recovering from events such as this.

Australia is a spoiled nation. They can expect my revenge Damir Dokic

"I will continue to work very hard on getting back to the top of my game and putting comments like these firmly behind me."

The WTA, the governing body of women's tennis, said it was concerned about the remarks and would do all it could to support Jelena's comeback.

"The Sony Ericsson WTA Tour is concerned about the welfare of Jelena Dokic and will continue to support her comeback in every possible way," said a spokesman.

Jelena began her career playing for Australia in 1998 before changing countries for Serbia in 2001, but recently she became estranged from her father and returned to Australia.

She lost to Virginie Razzano of France in the first round of the Australian Open on Friday.

Damir has not spoken to his daughter in two years.

In the past he has claimed the Australian Open draw was rigged, been ejected from the US Open in 2000 for abusing staff about the price of a salmon lunch, and smashed a journalist's phone at Wimbledon.

"Australia, with the help of Croatia and the Vatican, have brainwashed my daughter," Damir told Kurir.