The New York skyline is seen in the distance as Royal Caribbean's Explorer of the Seas enters New York harbour on January 29, 2014. The Explorer of the Seas cut short its Caribbean cruise following an outbreak of gastrointestinal illness. Picture: Eduardo Munoz

Bayonne, New Jersey - Passengers staggered off a Royal Caribbean ship reeking of vomit and diarrhoea at its home port on Wednesday after their cruise was cut short by an apparent stomach bug that felled nearly 700 vacationers and crew.

Cheers erupted from the Explorer of the Seas as the vessel pulled into Bayonne, New Jersey, in New York Harbour.

Passengers disembarking soon afterward recalled the nightmare of falling ill during the Caribbean cruise, being quarantined in their rooms, and putting everything they touched into biohazard bags.

“I had three days of sickness and quarantine,” recalled Susan Rogutski of Catawissa, Pennsylvania, who came down with gastrointestinal symptoms so severe the first day of the trip that she had to be physically dragged to the sick bay.

Carl Kern of Franklin Lakes, New Jersey, said the ship's hallways smelled of diarrhoea and vomit.

“Another passenger we became friends with said he went into the men's room and someone had gotten sick right on the floor and he stepped in it. It was bad,” Kern said.

Altogether, 630 passengers and 54 crew fell ill aboard the ship that departed Bayonne on January 21, Llelwyn Grant, spokesman for the US Centres for Disease Control and Prevention, said on Wednesday. Illness struck about 20 percent of the 3 071 passengers and roughly five percent of the 1 166 crew aboard the ship, he said.

Its planned 10-day cruise was cut short by two days when it returned to its home port on Wednesday.

Kern's wife, Fran Kern, was among the unhappy passengers who said the compensation being offered by Royal Caribbean, including 50 percent off a next trip, was inadequate.

“We were really disappointed. We've never been to many of these ports, so to pay all this money and not get to the ports is very disappointing,” she said.

“We aren't cruisers like some people. We should have gotten a full refund,” she said.

Other passengers, including Rogutski and her husband, Leonard Rogutski, felt Royal Caribbean responded well to the crisis and said they would take a cruise again someday.

“Though it was a bad situation all around, and it was very bad, Royal Caribbean bent over backwards to provide everything we needed,” Leonard Rogutski said. “The problem was it happened so quickly, there were so many cases, they weren't ready for what happened.”

The CDC said on Wednesday that the cause of the sickness was still under investigation and that stool samples collected from sick passengers were being taken off the ship and rushed to CDC labs for study.

“We're basically citing this as a gastro infection until we have the test results,” Grant said.

An environmental safety officer and an epidemiologist boarded the ship in St Thomas in the US Virgin Islands on Sunday to help determine the proper response to the outbreak.

While at sea, the ship's crew stepped up cleaning and disinfection procedures, the CDC said.

The cruise line said it believes the illnesses are consistent with norovirus, a highly contagious virus spread from an infected person, contaminated food or water, or by touching contaminated surfaces, according to the CDC.

Royal Caribbean said it was co-operating with all investigations and was disinfecting the Explorer of the Seas from top to bottom.