The Civil Aviation Authority (CAA) is investigating an incident where a plane slid off the runway at Christchurch Airport.

The NZ525 flight from Auckland to Christchurch on March 6 ended up on a section of grass off a runway at Christchurch Airport after the plane landed at 12.37pm.

Passenger Peter Jacobson, a pilot who had clocked up more than 10,000 flight hours himself, said the conditions on the day were unusual in that it was raining heavily and there were northwesterly winds.

The Boeing 737 aircraft landed on a shorter runway at Christchurch Airport than normal because of the winds, he said.

"It felt like a normal touchdown and normal braking, then ... I felt like the plane was trying to turn right, but it was still going straight ahead.

"We ended up on the grass, completely off the runway."

Jacobson said he wondered whether the weather conditions, use of the shorter runway, and the recent application of Gilsonite to several runways at the airport had played a part in the aircraft sliding onto the grass.

Gilsonite is a pavement sealant that acts like a cost-efficient "sunblock" for low traffic airside pavements.

A statement from Fulton Hogan in December stated the company had applied Gilsonite to 400,000 square metres of the airfield at Christchurch Airport so far to help reduce its ongoing maintenance costs.

An Air New Zealand spokeswoman confirmed the March 6 incident happened, but would not say what caused the aircraft to leave the runway.

"I can confirm the Boeing 737 aircraft momentarily lost traction while turning at low speed from the runway onto a taxiway to taxi to the gate and crossed an area of grass for a short time," she said.

"The aircraft underwent a thorough inspection but required no further engineering attention."

A CAA spokesman said initial inquiries suggested the plane's nosewheel "slid onto grass" and the crew used thrust to return the aircraft to the taxiway.

The aircraft was taxied to the terminal and passengers were able to disembark normally.

The plane was then quarantined and the cockpit voice recorder and the digital flight recorder were impounded.

The Transport Accident Investigation Commission were informed of the incident and the aircraft's crew returned to Auckland for debriefing, the CAA spokesman said.