RAGLAN - Four men were killed when their helicopter crashed into a cold, cloud-covered Waikato mountain yesterday.

The helicopter, carrying a police technician, the pilot and two passengers, crashed as it headed up Mt Karioi, near Raglan, where the men were to test a number of radio repeater stations, including one used by the police.

Two of the men were brothers from Raglan: Kevin Barry Lee, a 35-year-old Telecom technician, and Gregory Francis Lee, 38, a fisherman, who had been offered a free ride in the blue-and-white Squirrel seven-seater helicopter.

Kevin Lee's partner, Karen Gerbich, said last night: "They were just wonderful boys. We are just so upset at this. I know the family are distraught."

The other victims were the pilot, David John Logan, 39, of Cambridge, and Hamilton police information technology technician Glen William Phillips, 33.

Police Inspector Kelvin Powell said there were few clues to why the helicopter went down in rugged bush near the southeastern side of the 756m summit, although the mountain had been shrouded in cloud all day and there had been strong wind gusts.

Raglan people were shocked and stunned as news of the tragedy filtered through the town.

At the Harbour View Hotel, dismayed patrons clustered around to watch television news reports of the crash.

Barman Adrian Wilson said he knew the Lee brothers well as keen kayakers who came in once in a while for a drink.

Fisherman Chris Powell said that only last Thursday, Greg Lee had helped him to free his fishing boat, which was stranded on Raglan Harbour's sandbar.

"I can't believe this has happened. I owe this man my livelihood and now this ..."

Don Waters, a Cambridge colleague of pilot Mr Logan, said last night that his friend had one of the "best sets of hands in the helicopter business."

"I'm a helicopter instructor and have known him for 12 years. He was a pro."

Acting Senior Sergeant Jim Casson, of Hamilton, said Mr Phillips was "well liked and will be well missed."

Two police officers spent last night camped near the summit guarding the crash scene. The bodies will be removed today.