ROSEAU, Dominica (AP) — Two California men on a gay cruise of the Caribbean were arrested yesterday in Dominica, where sex between two men is illegal.

Police Constable John George said police boarded the cruise ship and arrested the two men on suspicion of indecent exposure and "buggery," a term equivalent to sodomy on the island. He identified the men as John Robert Hart, 41, and Dennis Jay Mayer, 43, but did not provide their hometowns.

George said the men were seen having sex on the Celebrity Summit cruise ship by someone on the dock.

The two were later charged with indecent exposure and are scheduled to appear before a magistrate this morning. If found guilty, they could be fined $370 each and face up to six months in jail.

The ship carrying about 2,000 passengers departed Puerto Rico on Saturday and arrived in Dominica yesterday. It departed for St Barts without the men, who are being held in a cell at police headquarters in the capital of Roseau.

The cruise was organised by Atlantis Events, a Southern California company that specializes in gay travel.

President Rich Campbell, who is aboard the cruise, said in a phone interview earlier that he thought the two men would be released. He later said in an email that the company has organised many trips to Dominica and would "happily return."

"Many countries and municipalities that gay men visit and live in have antiquated laws on their books," he said. "These statutes don't pose a concern to us in planning a tourist visit."

Campbell said he expects the two men to be released today and that they only face misdemeanour charges.

"The guests actions were unfortunate but minor in this case and have no bearing on our overall guest experience," he said via email.

The presence of gay cruises in the Caribbean has riled several conservative islands including Jamaica and Grenada, where anti-sodomy laws are enforced with strong backing from religious groups.

According to Cruisemates.com, no gay cruise lines sail to Jamaica or Barbados for fear of homophobia and possible violence. It said other places like the US Virgin Islands welcome gay cruises.

In 2010, the Cayman Islands rejected the arrival of an Atlantis gay cruise amid protests from religious groups even though homosexuality is legal on the archipelago.

Don Weiner, a spokesman for Atlantic Events, referred all questions to Campbell, including why the company organised a trip to Dominica and whether it knew about the island's anti-sodomy laws.

Elizabeth Jakeway, a spokeswoman for Celebrity Cruises, referred all questions to Atlantis.

The last time authorities in the Caribbean intervened on a gay cruise was in February 2011, when agents with US Customs and Border Protection arrested a California man aboard the Allure of the Seas, which had docked in St Thomas. The man, Steven Barry Krumholz of West Hollywood, pleaded guilty to selling ecstasy, methamphetamine and ketamine to fellow passengers.