Captain Scott's historic Terra Nova Hut in Antarctica has been badly hit by floods, says the trust working to conserve the largest of the "heroic era" huts on the frozen continent.

The Ross Island hut is the biggest historic building in Antarctica and was the base for Antarctic explorer Captain Robert Scott, and was built in January 1911 for his ill-fated 1910-1913 expedition to the South Pole.

Antarctic Heritage Trust chairman Nigel Watson said flood water had seeped inside the hut and had frozen: "It was a major shock to us. There was significant evidence of flooding."

The damage was found by trust workers on an expedition to conserve Terra Nova and also Sir Ernest Shackleton's Nimrod Hut. The four-man restoration team, most of whom are from New Zealand, took more than a week to remove the ice. It was not known if warmer temperatures or heavier snow caused the flood, Mr Watson said.

Scott and his men never returned to Terra Nova. On reaching the South Pole in January 1912, they found the Norwegian flag already flying there, and all five Britons died on the return trip.

The hut was also used by the Ross Sea party of Shackleton's transantarctic expedition of 1914-17. It is still packed with provisions of food, clothing, equipment and horse gear from the era. Relics nearby include dog skeletons, instrument shelters, stores and rubbish dumps, and there is also a memorial cross to three of Shackleton's men, who died in 1916.

Terra Nova, at Cape Evans, is one of three huts in New Zealand territory on Ross Island. Hut Point dates back to Scott's 1901-04 Discovery expedition and Nimrod to Shackleton's 1907-09 expedition.

The trust team spent a month doing restoration work, including repairing boards and fabric, and preserving food left by Shackleton at Nimrod. This had deteriorated to a point where it posed a potential threat to wildlife.

Nimrod Hut is listed among the 100 most significant buildings in the world by the World Monument Fund and is managed by the trust on behalf of the international community.

The restoration work was paid for by the Government and American Express, with additional funding from private and corporate donors in the United States and Britain.

"This was hugely significant [work] in terms of trying to conserve and save a legacy of the early exploration," Mr Watson said.