Wellington  - Two Australian brothers died when they were crushed under an estimated 100 tons of falling ice as they took photographs on New Zealand's Fox Glacier on Thursday.

The men, in their early 20s, were with their parents and extended family on a vacation trip to New Zealand.

A 30-metre wall of ice collapsed on top of them after they crossed safety barriers to get a closer look at the terminal face of the 14- kilometre long glacier.

The body of one of the victims was recovered but police said the threat of more falling ice made it too dangerous to reach the other.

As dawn broke on Friday, Constable Tony LeSueur said that police were liaising with Department of Conservation (DOC) staff to assess whether the ice structure had changed enough for another attempt.

Rob Jewell, chief executive of Fox Glacier Guiding, told Radio New Zealand the group went onto the glacier on their own without guides.

"Unfortunately, they have made the decision to go past the safety barrier there," he said. "There is a designated viewing area that has signage - a roped off area - where you can safely view the glacier."

DOC area manager Jo Macpherson told TV3, "The terminal face of the Fox Glacier is very steep at present and subject to random ice collapses."

She said the Glacier Valley, on the west coast of the South Island, which is one of New Zealand's biggest tourist attractions, was a safe place for visitors, as long as they took notice of warning signs and did not go beyond barrier ropes.

The department said in 2007 that almost a third of the 600,000 visitors to the glaciers on the west coast of the South Island ignored warning sings and entered danger zones. (dpa)