The wreckage of a helicopter that crashed and killed all seven people on board at Fox Glacier.

The South Island helicopter firm involved in a crash at Fox Glacier that killed seven people has been grounded over safety concerns six months later.

The Civil Aviation Authority suspended the Air Operating Certificate (AOC) of James Patrick Scott, whose company, Alpine Adventures, has operated flights in Fox Glacier, Franz Josef, and Tekapo.

Civil Aviation Authority (CAA) director Graeme Harris confirmed the suspension while the CAA investigated concerns about the safety of the operation.

SUPPLIED Mitch Gameren died along with six tourists in a helicopter crash on Fox Glacier in 2015.

All 15 of the company's helicopters were grounded after flights were suspended on Friday night.

Harris said the suspension action was taken in the public interest while his doubts about the safety of the operation were resolved.

"The action taken did not in any way pre-determine the outcome of the investigation to be carried out," he said.

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The November 2015 crash killed 28-year-old Kiwi pilot Mitch Gameren and six tourists: Andrew Virco of Cambridge in England, 50, Katharine Walker of Cambridge in England, 51, Nigel Edwin Charlton of Hampshire, 66, Cynthia Charlton of Hampshire, 70, Sovannmony Leang of New South Wales, 27, and Josephine Gibson of New South Wales, 29.

Gameren's mother, Adrienne Bray, said she was surprised to hear the company's licence had been suspended.

"We haven't heard anything for months except when they got more parts of the helicopter off the mountain. We've been told we won't have any answers until May next year," she said.

She said Gameren's father had sent letters to the families of the tourists who had died.

Scott operated under trading names Fox & Franz Heliservices, Tekapo Helicopters, and Makarora Helicopters.

Alpine Adventures organisational systems manager Barry Waterland said the CAA suspended the licence at 4.30pm on Friday.

"It did come as a shock to us. At this stage the suspension is for 10 working days but we are working with the CAA to endeavour to bring that forward if possible," he said.

"We have got to work through a number of areas that they have looked at for us to enable us to carry on. We are working now to get everything in order to get our certificate back again."

He declined to say which areas were being looked at.

"Part of it is related to the accident on the glacier and the high profile investigation and audits looking at us," he said.

Another helicopter company in the area was taking tourists who had bookings on flights.

Alpine Adventures website said the company employed nine pilots and up to 17 ground crew, office staff and management.

Managing director Scott had over 30 years of experience operating helicopters, and the company was a member of the Aviation Industry Association and the Mt Cook & Westland National Parks User Aviation Group.

The company's Squirrel helicopter was on a tourist flight when it crashed into a crevassed area of the 13 kilometre-long glacier.

It was several days before the bodies and some of the wreckage could be recovered. Further wreckage was recovered in April this year, including belly panels and helicopter fragments.

The Transport Accident Investigation Commission's inquiry was not expected to be completed before May 2017.

* A previous version of this story cited Alpine Adventures' website, which said it operated Kaikoura Helicopters. Kaikoura Helicopters owner Dave Armstrong says his company is not connected to Alpine Adventures or Scott's other operations.