Gastro outbreak strikes Syd-bound cruise

Another cruise ship on its way to Sydney has been hit by a bout of gastro, this time striking down 158 passengers.

The outbreak of norovirus gastroenteritis happened aboard the Diamond Princess cruise ship which arrived in Circular Quay on Thursday morning after a 12-day trip to New Zealand.

It's the third incident of gastro on board cruise ships in the past eight weeks.

South Eastern Sydney Local Health District told AAP the passengers and a small number of crew on board the Diamond Princess had come down with a bug and were attended to by the ship's doctor.

It's believed passengers were told to stay in their cabins and people were unable to serve their own food as the crew worked to contain the illness.

There were no medical disembarkations or hospitalisations.

The outbreak was contained on the final day of the cruise, Princess Cruises said in a statement.

Around 35 of more than 2800 passengers were still affected by the gastro bug, a Princess Cruises spokeswoman said.

New passengers boarding from Sydney on Thursday were advised there would be a short delay because of additional cleaning including public areas, cabins and hard surfaces.

There have been three incidents of gastro on board cruise ships in the past eight weeks.

Passengers on the P&O cruise ship Pacific Eden labelled it a "floating disaster" after about 50 of the 1500 on board were taken ill with norovirus over the Christmas period.

In mid-December, a gastro outbreak affected more than 180 passengers aboard Royal Caribbean's Explorer of the Seas during a two-week return trip from Sydney to New Zealand.

In October, more than 170 passengers were sick with a stomach bug during an eight-day cruise from Sydney on Royal Caribbean's Radiance of the Seas.