Divers who have returned to the wreckage of the liner Titanic after 15 years have been surprised by the rapid rate of deterioration.

An international team of deep-sea divers surveyed the sunken ship 3,800m down in the Atlantic and found that while parts of the ship are in surprisingly good condition, other features had been lost to the sea.

The worst decay was seen on the starboard side of the officers' quarters, the BBC said. 

Titanic historian Parks Stephenson was quoted as saying that the whole deck house on that side is collapsing, taking with it the state rooms.  

The deterioration is caused by strong ocean currents, salt corrosion and metal-eating bacteria are attacking the ship.

The ship hit an iceberg on its maiden voyage from Southampton to New York in 1912. Of the 2,200 passengers and crew onboard, more than 1,500 died. All the survivors have since passed away.

Diving expedition scientist Clare Fitzsimmons, from Newcastle University, said microbes on the shipwreck are eating away the iron of the wreck itself, creating 'rusticle' structures that are so fragile that they can crumble into a cloud of dust if disturbed.