The victim, a 40-year-old Filipino man, died at about 3 p.m. Friday as he was being airlifted to hospital in the Netherlands, said a spokeswoman for Hampshire police in southern England.
"A 49-year-old Filipino man has been detained on the ship by the captain under section 105 of the Merchant Shipping Act," she added.
"Four detectives and three crime scene investigators have flown to Norway and boarded the ship at Bergen.
"While en route back to the United Kingdom, the police officers will be speaking to any members of the ship’s crew who may have witnessed the incident," the spokesman said.
Hampshire police officers are conducting the investigation because the 1,132-foot French-built liner is registered in Southampton, on England’s south coast.
The vessel’s owners, Cunard, are now in the process of contacting the dead man’s next of kin in the Philippines.
He suffered serious head injuries after an alleged row with another member of staff, Cunard spokesman Eric Flounders said.
Flounders said the crew member accused of causing the injuries was confined to his cabin until police arrived.
"The cruise will continue as normal and none of our passengers have been affected. It is due back in Southampton on Wednesday," he added.
Cunard’s flagship was launched in September 2003 and made its maiden voyage in January 2004. It can carry up to 2,620 passengers, with a crew of 1,253.
The Queen Mary II cost an estimated $797 million to build and travels to destinations including New York, the Caribbean and Canada.