CARACAS - Venezuela quarantined a Spanish cruise ship on Wednesday after three crew members were diagnosed with the H1N1 flu virus and Barbados and Grenada refused to allow its passengers to disembark.

The cruise ship, owned by Royal Caribbean Cruises , is docked off the Venezuelan island of Margarita and the 1,200 people aboard will not be allowed off for a week, Venezuelan officials said.

"The virus was detected in three crew members and the boat must now stay in quarantine until June 24," state health official Jorge Alchaer said in comments printed by the government news service.

On Monday, the Ocean Dream operated by Pullmantur Cruises docked in Grenada, but no one was permitted to leave the ship because of reports several people on board had flu-like symptoms, a spokesman for Grenada's Health Ministry said.

The cruise liner's next destination was Barbados on Tuesday, but health officials refused to let the ship dock because 43 crew members exhibited flu-like symptoms, the Barbados Ministry of Health said in a statement.

Miami-based Royal Caribbean, which owns Pullmantur, said it could not comment on the situation. Pullmantur representatives were not immediately available for comment.

Many of the small island states in the eastern Caribbean depend on cruise ship arrivals as an important source of foreign exchange for their vulnerable economies.

A number of Caribbean states have reported confirmed cases of the H1N1 swine flu, which was declared a pandemic by the World Health Organization last week. Venezuela has confirmed at least 45 cases, with no deaths. One person died from the virus in nearby Colombia.

Royal Caribbean Chief Executive Richard Fain said last week the flu outbreak had "a short, but highly disruptive impact to our operations," although he added vessels were returning to their original itineraries.

The launch of a Pullmantur cruise targeting Mexican nationals, the Pacific Dream, had to be canceled because of the H1N1 outbreak in Mexico, the epicenter of the pandemic.

(Reporting by Frank Jack Daniel in Caracas and Jane Sutton and Pascal Fletcher in Miami; Editing by Peter Cooney)