Pauline Hanson's appeal was upheld and her conviction quashed

Ms Hanson, founder of the anti-immigration One Nation party, left jail on Thursday.

"I got caught up in a system that I saw fail me and I am so concerned now for the other women behind the bars... and men," she said.

The party's co-founder, David Ettridge, has also seen his conviction quashed.

Ms Hanson's appeal was upheld unanimously by three judges on the Queensland Court of Appeal.

This red-haired, hard-edged, twice-divorced mother of four shook the political establishment Profile of Pauline Hanson

They said her conviction was unsafe.

Ms Hanson, 49, was not in court for the hearing, but a small group of her friends and family welcomed the decision.

Her sister, Judy Smith, told reporters: "I am angry that she has been 11 weeks in jail where she shouldn't have been."

Ms Hanson's supporters are now demanding a national inquiry into her treatment by the authorities.

"There are questions to be asked at state and federal level about Pauline's investigation, prosecution and incarceration," said Bill Flynn, One Nation leader in the Queensland state parliament.

Immigration

Ms Hanson had been found guilty of fraudulently registering her One Nation party in the Australian state of Queensland.

Prosecutors said that she had used the names of supporters as genuine members of her party in order to qualify for electoral $300,000 in electoral funding.

She and David Ettridge each spent 78 nights in jail.

Pauline Hanson was a former fish-and-chip shop owner who burst onto Australia's political scene in 1996 when she won a seat as an independent in the federal parliament on a platform opposing immigration and what she saw as handouts to aborigines.

A year later she set up One Nation, along with David Ettridge.

Their party won almost 25% of votes in a state election in 1998, but after that support began to fade, and Ms Hanson lost her own seat in a federal vote in the same year.

Internal rivalries began to pull One Nation apart and Ms Hanson left the party last year to concentrate on her legal difficulties.

Her conviction and jailing in August led to an upswing in sympathy and support. A BBC correspondent in Australia, Phil Mercer, says her release from jail could now re-ignite her political career.