Four tourists from Britain and two from Australia are among seven people who died when a helicopter crashed on a scenic New Zealand glacier, police said.

Rescuers on Sunday were working to recover the bodies from Fox Glacier, where the wreckage remained wedged in a crevasse. Police said in a statement the rugged terrain was making the operation "extremely challenging."

Police named the victims as Britons Nigel Charlton, 66, and Cynthia Charlton, 70, of Hampshire, and Katharine Walker, 51, and Andrew Virco, 50, of Cambridge. Australians Leang Sovannmony, 27, and Josephine Gibson, 29, of South Australia, also died. The New Zealand pilot was identified as Mitchell Gameren, 28, of Queenstown.

Fox Glacier is a popular tourist destination on New Zealand's South Island.

Grey District Mayor Tony Kokshoorn said the weather was "not ideal for helicopter flying," with intermittent rain showers and low clouds.

Kokshoorn said that the region had been experiencing a bumper start to the Southern Hemisphere tourist season, but that bad weather had been putting pressure on some tourist operators.

"It can be a fine line," he said. "Operators are doing their best to get people up there, but obviously something went badly wrong."

He said that the glaciers in recent years have been retreating and that the only way to view them up close is by helicopter. He said operators offer different packages, and a basic trip typically involves a 10-minute flight to the top of the glacier, where tourists can walk around for about a half-hour before returning.

Peter Northcote, a spokesman for the Transport Accident Investigation Commission, said the helicopter was ferrying tourists at the time of the crash. He said a team of investigators was planning to survey the scene over the coming days.

Nine people died in 2010 when a skydiving plane crashed near the same glacier.

New Zealand relies on tourism as a major source of revenue, but has been criticized by some people as having safety standards that are too lax. The parents of four tourists who died in the 2010 crash near Fox Glacier later wrote to New Zealand Prime Minister John Key to urge him to improve safety measures in the industry.

Kokshoorn, the mayor, said he hopes authorities complete a thorough investigation into the latest crash to ensure that the industry is safe and that tourists can have confidence that operators will make the right call in bad conditions.