Cheung Chau residents are considering suing a company that wants to trademark the "peace" stamp on the traditional white buns that are a feature of the island's annual festival.
The pink stamp has been used for the past decade during the week-long Cheung Chau Bun Festival, when official bakeries make the buns and leave them outside so that visitors can watch them getting stamped. It is also used on other festival products.
Festival organiser Kwong Sai-loi said the stamp belonged to the people of Cheung Chau.
He was responding to a move by private firm A Gimmick Limited, based in Kwai Chung, which applied to the Intellectual Property Department to register the trademark in November.
Islands district councillor Lee Kwai-chun said: "If the stamp is trademarked it could mean others won't be able to use it any more on their products.
"I believe the company is trying to monopolise the market."
Kwong said he would rally residents to sue the company if the trademark was approved. "This company didn't create the stamp for the buns. It is unreasonable for them to try to claim ownership of it as the stamp belongs to all the people of Cheung Chau."
The festival, which begins on May 3, was in 2011 listed by the Ministry of Culture as part of the nation's "intangible cultural heritage". Thousands of people descend on the small island to see one of the most popular events of the festival, in which contestants scramble up an 18-metre tower to snatch buns - with those located higher up worth more points.
In its trademark application of November 11, A Gimmick says it sells products such as toys and food. It could not be reached for comment. The department said last month it had received the application. A Leisure and Cultural Services Department spokesman said it and the festival committee were seeking legal advice and may try to block the application.