A Pacific Blue plane flying to Wellington was diverted to Christchurch and declared an emergency landing overnight.
Flight DJ68 was inbound from Brisbane when a "cockpit light illuminated" causing alarm, a Pacific Blue spokeswoman said.
"The captain declared an emergency landing as a precautionary measure only."
She said the plane was diverted to Christchurch due to the engineering support there.
It landed safely about 12.40pm. There were 41 passengers on board.
"They were kept in the airport in Christchurch. Because of the late hour we didn't have a crew and obviously we couldn't head to Wellington because of the curfew."
The spokeswoman said the passengers stayed at the airport and were flown to Wellington about 6.45am today.
She said the plane was back in service after being inspected.
A Civil Aviation Authority spokeswoman said the event had not been reported to the agency yet, but the airline had 14 days to do so.