Police say they have grave fears for the survival of a pilot who disappeared while flying a helicopter near Lake Wanaka yesterday.

Pilot Morgan Saxton, 31, and the Robinson R22 helicopter he was in were last seen near Minaret Station towards the northern end of Lake Wanaka at 6pm.

Earlier today searchers found a floor mat, first aid kit and helicopter seat-back on the eastern shoreline of the lake. Later, a helmet and flight jacket were found separately, as was an oil slick near Mou Waho (Pigeon) Island.

Wanaka police Detective Sergeant Derek Shaw said police had taken over the search, which was now focusing on the area where the oil slick was sighted.

“While searchers remain hopeful of a positive outcome they are also realistic and hold grave fears for the survival of Mr Saxton,” Shaw said.

“Over the next two days a heavy commercial barge will be positioned over the source of the oil slick in an attempt to locate any wreckage of the helicopter and hope that that will shed some light on the whereabouts of Mr Saxton.”

Local police were consulting with both their own Wellington based dive squad and New Zealand Navy divers for advice and assistance in the next phase of the search.

Shaw said it appeared Saxton was on a repositioning flight from Haast to Wanaka in preparation for frost fighting in the region’s vineyards this morning.

Saxton is on bail, pending appeal, after being jailed in February along with his father, David, for over two years after being found guilty of stealing hundreds of thousands of dollars worth of Ngai Tahu greenstone from south Westland.

They were bailed in June and face restrictions on flying and have to live in Haast.

The men are respected rescue pilots and are credited with many rescue missions in South Westland, Fiordland and Central Otago.

Their convictions enraged many West Coasters, some of whom protested the jailings.

The pair run Heliventures in the Haast region. The missing helicopter is not believed to be one belonging to the company.