Canberra: A popular right-wing commentator was yesterday found guilty of breaking Australian discrimination law by implying that fair-skinned Aborigines chose to identify as indigenous for profit and career advancement.

Federal Court Justice Mordy Bromberg ruled that fair-skinned Aborigines were likely to have been "offended, insulted, humiliated or intimidated by the imputations" included in columnist Andrew Bolt's two articles published by the Herald Sun newspaper in Melbourne in 2009.

Bromberg ruled out Bolt and his publisher's defence under a clause of the Racial Discrimination Act that exempts "fair comment". Bromberg said he will prohibit the reproduction of the offending articles and will consider ordering the newspaper to publish a correction if it doesn't print an apology.

Bolt, who writes opinion pieces for newspapers around Australia and hosts a nationally broadcast weekly public affairs television programme, described the ruling as a defeat for freedom of speech.

"This is a terrible day for free speech in this country," he told reporters outside court. "It is particularly a restriction on the freedom of all Australians to discuss multiculturalism and how people identify themselves."

Publisher Herald and Weekly Times Pty Ltd, a subsidiary of Rupert Murdoch's News Corp, said it was considering lodging an appeal.

"We defended the action because we believe that all Australians ought to have the right to express their opinions freely, even where their opinions are controversial or unpopular," the publisher said in a statement.