SYDNEY - AN AUSTRALIAN writer has been formally charged with insulting the Thai royal family after being held in custody in Bangkok since September, his lawyer said on Saturday.

Harry Nicolaides, 41, will plead not guilty to the charge when he faces court on Jan 19, lawyer Mark Dean told the Australian Broadcasting Corporation.

Mr Dean said the case, which relates to passages in a novel which has since been withdrawn from publication, was being needlessly dragged out.

'It's very difficult to see why it is that Harry Nicolaides has been held in remand for the maximum period of 84 days for the purpose of investigating the case, when the case concerns the publication of three sentences in a book three years ago,' he said.

'He was held yesterday in extremely crowded prison conditions below the Thai criminal court - I understand from his partner who saw him there yesterday afternoon that he was in an extremely distressed state,' Mr Dean said.

'Everybody's very concerned for his welfare and his elderly parents are extremely distressed by the situation that Harry's currently in.'

Nicolaides was detained at Suvarnabhumi Airport departure lounge in early September on an arrest warrant issued two-and-a-half years earlier.

Immigration police official Lieutenant Colonel Pakpapong Sai-ubol said at the time that Nicolaides had previously worked as a university lecturer while living in northern Thailand.

A spokesman for Australia's foreign ministry told AFP that Nicolaides had been denied bail on a charge that 'relates to a passage in a novel published by Mr Nicolaides in 2005 considered offensive to the Thai monarchy'.

'He has been charged under a provision of the Thai penal code section 112 which states that 'whoever defames insults or threatens the king, the queen, the heir apparent or the regent shall be punished with imprisonment of three to 15 years',' the spokesman said. -- AFP