More than 90 authors, including Nobel winner J. M. Coetzee, have condemned China for refusing an HIV-positive Australian writer entry to the country for a government-sponsored tour.

Robert Dessaix revealed his health status in his application for a visa which was refused without explanation.

The Australian Society of Authors condemned the decision, penning an open letter signed by more than 90 writers including Schindler's Ark author Thomas Keneally and 2004 Commonwealth Prize regional winner Michelle de Kretser.

"This was an act of discrimination that appears to be founded in fear or ignorance and is behaviour unworthy of any nation that desires to be seen as enlightened and civilised," the letter says.

"We ask the Chinese government to explain its decision as a matter of urgency and to offer Mr Dessaix the public apology to which he is entitled."

Mr Dessaix, 65, had been due to speak at Shanghai's International Literary Festival which featured writers such as Su Tong, Scott Turow and Junot Diaz.

"It's mediaeval," the writer told The Sydney Morning Herald this month, adding that Australian officials had been given no reason for his rejection but believed his health status was the stumbling block.

"I feel snubbed and insulted, of course, and also humiliated. There had been interventions at the highest level on my behalf, but they were refused, so I see it as a snub to Australia, not just to me."

The Australian Department of Foreign Affairs said the government did not comment on individual cases but was aware that Mr Dessaix had been unable to secure a visa for China. "The Australian government has, through diplomatic channels, spoken with Chinese authorities on a number of occasions over recent weeks in support of Mr Dessaix's visa application," a spokeswoman said.

"The Australian government is disappointed that Mr Dessaix was not able to take up his invitation to attend the event."

Mr Dessaix is a novelist, essayist and travel writer whose books include A Mother's Disgrace, Night Letters and Corfu.