Two Chinese tourists scream in horror as a South Island avalanche rumbles down a mountain and buries a Sydney man, who later died, new video footage shows.

Earlier this afternoon, ONE News revealed dramatic footage of the start and aftermath of an avalanche near Queenstown which overwhelmed Roger Greville, who was on a heli-skiing adventure.

The 58-year-old was pulled from avalanche debris near the Devil's Staircase just before 3pm yesterday, but died a short time later, police said.

The video was taken on a GoPro by a Chinese man, known as Mr Jone, who was also heli-skiing at the time and sent to ONE News.

A longer version of the video shows the start of the avalanche, and what appears to be a skier being engulfed by the heavy snow.

The Chinese man in shot can be heard shouting, "careful, careful" as the massive wave of white comes rumbling down the mountain side.

Mr Jone also filmed the aftermath of the avalanche where a rescue team is seen searching the debris and pulling skiers to safety.

He said he was with a friend when the avalanche came crashing down the mountain slope, and this morning took the video to police.

Jonathan Wallis, the co-director of the heli-skiing company Mr Greville was using, told ONE News he was aware of the avalanche footage and said it was now being used in a police investigation into the incident.

He said the company, Southern Lakes Heliski, will resume operations tomorrow, after being temporarily suspended today.

A Southern District Police spokesman said the footage may be used as evidence in the investigation into Mr Greville's death.

A post-mortem examination was carried out this morning.

We never presume that there is not going to be an avalanche - Alpine Cliff Rescue team leader Chris Prudden

Alpine Cliff Rescue team co-leader Chris Prudden told ONE News that the recent cold snap had dumped fresh snow in the area, but there had been little wind, leaving the snow quite stable.

He said while heli-skiing was performed by "top people ... no one is ever 100 per cent safe".

"We never presume that there is not going to be an avalanche ... Conditions were not particularly acute for one [yesterday], there may have been a few terrain traps, a number of people on the slope. There could be a number of reasons why this happened."

Roger Greville Source: Supplied

Mr Greville was one of a party of five on a guided trip through the Hector Mountains.

The scene after yesterday's avalanche. Source: Supplied

A Southern Lakes Heliski helicopter. Source: Supplied

The company's director Julian Field yesterday said it was a "tough day".

"Heli-skiing is not dangerous however, like any adventure activity, it carries inherent risk," he said in a statement.

"We take our responsibilities very seriously which is reflected in the fact that this is the first incident of this kind for our company and its predecessors in over 30 years of

operations."