"Norway will by this contribute to the global system for ensuring the diversity of food plants. A Noah's Ark on Svalbard if you will," Norwegian Agriculture and Food Minister Terje Riis-Johansen said in a statement.

The doomsday vault would be built near Longyaerbyen, Svalbard's main village, with space for three million seed varieties. It would store seeds including rice, wheat, and barley as well as fruits and vegetables.

It would be a remote Arctic back-up for scores of other seed banks around the world, which may be more vulnerable to risks ranging from nuclear war to mundane power failures.

"Gene banks can be affected by shutdowns, natural disasters, wars or simply a lack of money," Riis-Johansen said.

Loss of genetic diversity would mean losing a part of cultural heritage. "We also reduce the ability of agriculture to meet new challenges relating to climate change, population increase, and so on," he said.

The seeds would be stored at -18 Celsius (-0.40F). If the power failed, the seeds would probably stay frozen.

"The temperature there is around -3C, -4C in the summer but we believe that even if the freezers broke down a suitable temperature would last for months," said Grethe Helene Evjen, a senior adviser at the Agriculture Ministry.

"This will be primarily a duplicate storage for plant seeds already stored elsewhere," she told Reuters. Seeds would remain the property of nations making deposits.

Norway would provide 30 million Norwegian crowns (US$4.94 million) to build the vault. Prime Minister Jens Stoltenberg would mark the start of construction during a meeting of prime ministers from the Nordic region on the island on June 19.

Norway has long talked of building the Arctic seed vault without previously taking action. For about 15 years some varieties of seed have been stored in a disused Svalbard mine under a plan to see if they can germinate after 100 years.