Pauline Hanson spent her first night in jail in a medical wing

Even Prime Minister John Howard, once a fierce rival, said on Friday that her three-year sentence for electoral fraud was "very long and very severe".

But Mr Howard dismissed claims from Mrs Hanson's supporters that she was victimised by mainstream political parties, who object to her extreme right-wing policies on immigration, race and law enforcement.

The verdict "wasn't inspired politically", he told a local radio station. "I've read this suggestion that it was a witch-hunt. It wasn't," he said.

Mrs Hanson's lawyers have launched an appeal against her sentence.

The founder of the anti-immigration One Nation party was jailed for electoral fraud on Wednesday together with the party's deputy director, David Ettridge, who was also given a three-year jail term.

This red-haired, hard-edged, twice-divorced mother of four shook the political establishment, provoked outrage, and inspired a legion of satirists Profile of Pauline Hanson

The pair was found guilty of illegally using the names of 500 members of a support group to register One Nation as a political party, as well as fraudulently obtaining almost A$500,000 (US$325,000) in electoral funds.

A survey by Channel 10 television found that 85% of callers were opposed to the sentence.

Photographs of her leaving the court in tears, and reports of her breaking down in her jail cell have fuelled calls for clemency.

One Nation's current president, Rod Evans, said his office had been swamped with calls of support and offers of assistance.

"They're very emotional and of course in shock and disbelief," he said.

Hanson's official website has compared her jail term to that of Nelson Mandela in apartheid-era South Africa, and a "fighting fund" has been launched to seek donations to help finance an appeal.

Her lawyers lodged the 12-point appeal with the Brisbane Supreme Court of Appeal, citing "interference by political identities of power".

But not everyone thought the sentence passed against Hanson was unjustified.

Outspoken Labor politician Mark Latham said she had recently campaigned for tougher penalties for criminals and "now she's got one".

Breakdown claims

Hanson herself is reported to be struggling to come to terms with her sentence.

"She seems to think it's all a bad dream that she's going to wake up from. She's depressed and very quiet," an officer at the Brisbane jail told the Herald Sun newspaper.

She is reportedly under 24-hour observation, and has been issued with sedatives to calm her down.

But her lawyer Chris Nyst insisted that Hanson was "doing fine", although she was "obviously very disappointed with what's happened".

He added that she still remained determined to overturn her conviction.