Rice is one of the world's most important crops

The Norwegian government will hollow out a cave on the ice-bound island of Spitsbergen to hold the seed bank.

It will be designed to withstand global catastrophes like nuclear war or natural disasters that would destroy the planet's sources of food.

Seed collection is being organised by the Global Crop Diversity Trust.

"What will go into the cave is a copy of all the material that is currently in collections [spread] all around the world," Geoff Hawtin of the Trust told the BBC's Today programme.

Mr Hawtin said there were currently about 1,400 seed banks around the world, but a large number of these were located in countries that were either politically unstable or that faced threats from the natural environment.

"What we're trying to do is build a back-up to these, so that a sample of all the material in these gene banks can be kept in the gene bank in Spitsbergen," Mr Hawtin added.

The Norwegian government is due to start work on the seed vault next year, when it will drill into a sandstone mountain on Spitsbergen, part of the Svalbard archipelago, about 966km (600 miles) from the North Pole.

Permafrost will keep the vault below freezing point and the seeds will further be protected by metre-thick walls of reinforced concrete, two airlocks and high security blast-proof doors.

The number of seeds and types of plants in the bank would be determined by the countries wishing to use it.