The death of two climbers in a fall on the Remarkables was tragic, and a guide's worst nightmare, says the alpine rescue specialist who was first on the scene.

Two men were on a climbing tour of the popular Grand Traverse route yesterday when they fell from the Grand Alta Ridge and died shortly before midday, tied together.

Leading another alpine tour near the bottom of the ridge, by chance, was Chris Prudden of Mountain Rescue.

He said it wasn't immediately clear what had happened, when he saw one person at the bottom of the hill and a guide at the top.

"It was pretty sad, pretty tragic... to see the end of that situation knowing full well that they'd fallen 300 metres - it's a hell of a long way in that steep terrain," he said.

A rescue helicopter was dispatched to the scene and removed one of the men, and police confirmed the deaths at about 4.30pm.

Efforts to recover the body of the second climber resumed this morning.

Mr Prudden said the conditions yesterday could have been a factor in the fall.

"It was very warm, a little bit of cloud wafting around the peak, and the snow was very soft and could be called unstable on areas of the Grand Traverse, although it's mostly rock exposed there now. That weak snow may well have been a component," he said.

Having worked full time in the Remarkables since 2002, Mr Prudden wasn't surprised a bad accident had happened on the 8-to-12-hour route along the high points of the Remarkables.

"Over the summer months there's a hell of a lot of people that go along there, a hell of a lot of people who solo along there, treating the place unfortunately way too casual," he said.

"It's technical terrain. It's very steep on either side. The only way off it is to go across it."

Every year he said he helped rescue people who had found the downwards trip a lot further than what they thought - and in September he helped rescue three people from the Grand Alta Ridge in snowy conditions.

RNZ understands the group involved in yesterday's fatal accident were with Aspiring Guides.

Mr Prudden said he hoped the lesson went out to the general public around Queenstown that they should treat the Remarkables with a lot of respect.

As for guides and regular climbers, he said "it makes you start to think about things."

"Essentially, our job as guides is to manage safety for others in the mountains and hopefully teach them things as well. I guess it's a guide's worst nightmare when things become unstuck," he said.

WorkSafe has been notified about the incident and is making initial inquiries.

Police said they were working to notify the victims' next of kin.