The latest novel from Haruki Murakami, Japan’s most celebrated literary export, has fallen foul of censors in Hong Kong, where it was ruled to be indecent by a tribunal and removed from display at a book fair.

Hong Kong’s Obscene Articles Tribunal announced last week that the Chinese-language edition of Murakami’s Kishidancho Goroshi, or Killing Commendatore, had been temporarily classified as “Class II – indecent materials”, according to the South China Morning Post. This means that it can only be sold in bookshops with its cover wrapped with a notice warning about its contents, with access restricted to those over the age of 18. The ruling has also seen the novel pulled from booths at the Hong Kong book fair, where a spokesperson said the novel had been removed proactively after last week’s ruling.

Due to be published in the UK this autumn, Killing Commendatore is “an epic tour de force of love and loneliness, war and art – as well as a loving homage to The Great Gatsby – and a stunning work of imagination from one of our greatest writers”, according to its British publisher Harvill Secker. It went on sale in Japan last year with midnight openings and queues of eager fans.

A spokesman for Hong Kong’s leisure and cultural services department told the Guardian that public libraries had already applied opaque wrappers and warnings to both the front and back covers of the book. “The library item will then be made available only to readers aged 18 or above upon request and borrow it,” he said.

The Taiwanese firm that publishes Murakami’s novel, China Times Publishing, said it had also been asked to remove it from its booth at the Hong Kong book fair, with exhibitors warned that selling “indecent” material could lead to booths at the fair being closed down, according to the paper.

The ruling has been widely criticised. Jason Y Ng, president of PEN Hong Kong, told the Guardian that “for a place that holds itself out as Asia’s world city, the Hong Kong authorities’ views toward sexuality and the literary treatment of it are archaic”.

“They are also arbitrary: who is to say Mr Murakami’s depiction of sex in Killing Commendatore is any more indecent than that in a James Joyce or Henry Miller novel? And yet the former is banned from a literary event and the latter is taught in school as classics,” Ng said.

A petition signed by almost 2,000 people is calling for a reversal of the tribunal’s decision, stating that it “makes Hong Kong the most conservative area in the Sinosphere, and will bring shame to the people of Hong Kong”.

The ruling follows the removal of children’s books with LGBT themes from library shelves in Hong Kong after pressure from an anti-gay-rights group. Titles including the award-winning picture book about two male penguins who fall in love and adopt a chick, And Tango Makes Three, were removed from public view and made available only on request after a lengthy campaign from an anti-gay focus group last month.

“Any citizen, gay or straight, should be equally outraged by such blatant censorship. We hope that civil society in Hong Kong will continue to stay vigilant to ensure that these isolated incidents don’t turn into a troubling pattern and eventually to a new normal,” said Ng.

PEN International recently submitted a report to the UN Human Rights Council highlighting its concerns about growing censorship in the region, and Rachael Jolley, editor of Index on Censorship, said recent restrictions “appear to be part of a worrying trend in China to be more restrictive about how sex is portrayed in books, and what is ‘allowed’.

“Book fairs are the last places we expect to see censorship, so it is worrying that we are seeing the new Murakami novel removed from the Hong Kong book fair’s booths. Book fairs are where people go to see a range of writing and we would call on the directors to make sure that they resist bids to censor which pieces of writing are on show,” said Jolley.