Dr Nitschke said Attorney-General Robert McClelland had referred the book to the board. The board's decision to hold a classification hearing is unusual, given Penguin Australia published the book more than three years ago.

It is understood the Attorney-General was reacting to newspaper reports that a Perth mother, Erin Berg, who committed suicide in May after travelling to Mexico, had read the book, which describes euthanasia drugs sold overseas.

Mrs Berg was suffering from serious post-natal depression but was not inflicted with a terminal illness.

The Classification Board has the power to ban the book altogether, restrict its sale and distribution, or make it a crime to sell or display it.

The chairman of the Classification Board, Donald McDonald, contacted Penguin Australia earlier this month and asked the publisher to submit a copy of the book that was written by Dr Nitschke and his partner Fiona Stuart.

Dr Nitschke, who was on his way back to Australia from Britain after establishing an on-line site for his controversial The Peaceful Pill Handbook, said Mr McClelland was reacting to pressure from what he claimed was a campaign being organised by the family of Mrs Berg.

''The book Killing me Softly has about one sentence referring to the fact that people go overseas to obtain euthanasia drugs,'' he said.

Dr Nitschke said the book was largely a discussion of the issue and had been used in school curriculum. Penguin Australia publishing director Robert Sessions said any ban on the book could cause significant disruption.

There were few copies of the book in bookstores and the ban would mostly inconvenience libraries.

''I submitted the book under protest,'' Mr Sessions said. He stressed that the publication was thoroughly examined by lawyers before publication and was a legitimate contribution to an important debate.

The Classification Board refused to confirm the reference had come from the Attorney-General's office, as alleged by Dr Nitschke.

A spokesperson for the Attorney-General refused to comment and said all matters regarding classification were dealt with by the Home Affairs Minister, Bob Debus, whose portfolio is part of the Attorney-General's Department.