"Kim has never said she wanted to become an Australian (citizen). On the contrary she has always said she was and will remain Belgian," her father Leo Clijsters was quoted as saying by local media on Wednesday.

"But as her manager I have to look at all options. We can't dismiss this without studying it carefully."

Asked about reports that Clijsters was considering Australian citizenship, Australia's Federal Department of Immigration told Reuters: "We can't confirm or deny that. For privacy reasons we can't comment on any case like that."

Clijsters, who is ranked fourth on the WTA Tour and beat Serena Williams to clinch the prestigious Tour Championship last month, pays the taxman between 50 and 60 percent of her earnings -- much less than footballers in Belgium, Leo Clijsters said.

"All I'm asking for is equality. This would make it harder for some of our best sportspeople to be based in Monaco," he said referring to the Mediterranean tax haven.

The teenager spends much of her time in Australia, home of long-term boyfriend and world number one Lleyton Hewitt, and has even posed snuggling up to koalas for photographers.

Leo Clijsters said the Australian authorities had drawn his attention to the country's "more advantageous tax rules" last year when Kim was thinking about buying an apartment in Adelaide.