Xavier High School in Albury printed the letter, written by former student Matt Price, in the latest edition of its alumni newsletter Xavier.

Mr Price said he was "trying to make the world free of homosexuals", who live lives devoted to "sex and drugs".

"The gay side of life, all it's ever been is going out and doing that sort of stuff — the world just really doesn't need that," he said.

Mr Price said he was a "cured" homosexual and now lived in Noosa working as a registered nurse.

Anti-discrimination campaigner Garry Burns blasted Xavier High's decision to publish the letter, saying he understood Mr Price's letter to mean that gays and lesbians should be killed.

"It says he wants the removal of homosexuals from the face of the earth and there's only one way to interpret that," Burns told ninemsn.

"There are people out there who will express that endorsement through bashings, murder and all sorts of things — they'll go out and say the Catholic Church is right: 'let's get a poof and kill him'."

The 52-year-old, who last year sued 2UE presenter John Laws after he called gay men "pillow-biters" on-air, said Xavier High officials "ran away and hid like Burmese kittens" after he asked them to apologise and make a $5000 donation to gay and lesbian support group Twenty10.

Burns said he hoped media reports, including one by gay and lesbian publication SX News, would pressure the school into making a statement.

An online copy of the newsletter on the school's website has been changed to remove all of Mr Price's comments about homosexuality.

Xavier High headmaster Neville Powells could not be contacted for comment although he addressed the remarks in a recent student newsletter.

"We live in a country where free speech is available to all," Mr Powells said.

"That said, I apologise for any offence caused — certainly none was intended. "Unfortunately on this occasion some elements of the published letter were not detected during the editing process and were included in the distribution."