British and Australian tourists are believed to be among seven people killed in a helicopter crash in one of New Zealand's best-known tourist spots, local police have said.

The pilot and six passengers were on board the aircraft when it went down at Fox Glacier on the remote west coast of the South Island in what have been described as poor conditions.

Four rescue helicopters were sent to the scene.

A paramedic and alpine rescue team were winched down to the crash site and confirmed there were no survivors.

A spokesman for the New Zealand Police said it is thought all six passengers were foreign tourists.

"It is believed two were Australians and four were from the United Kingdom," the spokesman said, adding that formal identification will take "some time."

"Police have been liaising with the embassies of the countries concerned to ensure the next of kin are advised of the situation."

Images of the crash site show the helicopter buried between walls of ice in a deep crevasse.

Police have said the remote location of the wreckage and poor weather conditions mean efforts to recover the victims will not take place until Sunday and could last several days.

Speaking of the recovery operation, Police Inspector John Canning said: "I'm not going to risk any more lives, we've lost seven."

According to Grey District Mayor Tony Kokshoorn, weather conditions were marginal at the time of the crash, with intermittent rain showers and low clouds.

"It was not ideal for helicopter flying," he told the AP news agency.

TVNZ producer Suzanne Burgess said search and rescue operations were initially hampered by a considerable amount of low cloud.

The helicopter is reported to belong to Alpine Adventures, which is one of many companies that run helicopter and private charter sight-seeing trips for tourists around the eight-mile-long glacier.