Movie director James Cameron talks to reporters at an event in Wellington, New Zealand. File picture: Nick Perry/AP

London — Filmmaker James Cameron and Titanic discoverer Robert Ballard are backing a bid by a group of British museums to acquire a collection of 5 500 artefacts from the sunken vessel.

The campaign announced Tuesday aims to raise $20 million (around R266 million) to buy the items from a private American company that salvaged them from the wreck.

The director of the 1997 blockbuster "Titanic," starring Leonardo DiCaprio and Kate Winslet, said there are grave concerns that the collection will be broken up and sold privately because that company has filed for bankruptcy.

"That's why people who feel some protective role have stepped up and kind of linked arms," Cameron said. "It's an incredible piece of history, an object lesson about human hubris. If it gets sold into private hands, it disappears from the public eye. It would be broken up and could never be reassembled."

Dr Robert Ballard, who discovered the wreck of Titanic in 1985, speaks at Titanic Belfast, Northern Ireland. Picture: Niall Carson/PA via AP

He said his expeditions to the undersea site have made him feel a responsibility to honour those who lost their lives on its doomed voyage in 1912.

The objects include a section of the ship's hull and a bronze cherub decoration from the ship's grand staircase. They were recovered from the wreck site during seven deep-sea expeditions between 1987 and 2004.

The bid for the artefacts comes from the Royal Museums Greenwich, National Museums Northern Ireland, Titanic Belfast and Titanic Foundation Limited. The National Geographic Society has pledged $500 000 to help fund the project.

Aoise Taggert, aged nine, looks at a model of the Titanic at Titanic Belfast, Northern Ireland. Picture: Niall Carson/PA Wire via AP

The bid was announced at Titanic Belfast at the location where the ship was designed, built and launched.

Ballard, who discovered the wreck in 1985, said the campaign is the "only viable option to retain the integrity" of the artefacts. He said the collection "deserved to be returned home to where its journey began."

The Titanic sank in the North Atlantic on its maiden voyage in 1912 after hitting an iceberg. More than 1 500 passengers and crew died.