Authorities have put a 1km no-go zone around the main wreckage site of a rescue helicopter that crashed at Mount Pirongia yesterday.

The Waikato Westpac Rescue Helicopter, a BK117, came down while flying to help an injured tramper on the mountain near Te Awamutu about 5pm yesterday. The three crew on board escaped injury and two more rescue helicopters were sent to the site to retrieve them and the injured tramper.

The Transport Accident Investigation Commission is investigating the incident and put a protection order in place for a 1km perimeter around the reported final main wreckage location near Wharauroa Lookout.

Photos on other media show the downed helicopter jammed into thick bush, with its rotor blades mangled.

The main wreckage location is 37° 59.43′S 175° 07.36′E, the commission said in a media release.

The order protects any wreckage within the exclusion zone, or “any identified aircraft type components found in the vicinity outside this area”.

It was signed by the commission’s acting chief investigator of accidents, Jim Burtenshaw.

“The evidence may assist in establishing the circumstances and causes of the accident. Anyone finding debris should report this to the police.”

It is not yet known how long the order would remain in place.