Nearly 10,000 new varieties of crops from around the world are being added to the "doomsday" seed vault in the Arctic as part of efforts to ensure global food security.

The Svalbard Global Seed Vault, on an island off Norway's northern coast, already stores 825,000 samples of seeds which represent 13,000 years of agricultural history.

The vault, managed by the Global Crop Diversity Trust (GCDT), provides a back-up to the network of seed banks around the world which store, grow and replenish thousands of varieties of crops - but which can be threatened by war, accidents and natural disasters.

Preserving different food plant varieties will help breed and develop crops that can withstand a changing climate, the trust said.

Marie Haga, executive director of the GCDT, said: "Crop diversity is essential if we are to provide more food, more nutritious food and affordable food for the poor.

"Maintaining crop diversity, and the genetic wealth it provides, is beneficial to all of us on this planet."