A 13-minute takeoff delay caused so much tension between two Air New Zealand pilots that the first officer was locked out of the cockpit on a flight between Perth and Auckland.

On May 21, flight NZ176 was delayed after the first officer was asked to undertake a random drug and alcohol test. This was enough to enrage the captain, for whom timeliness was a matter of great pride.

Locked out: Air New Zealand described the pilots' mid-air falling out as 'unfortunate'. Credit:Bloomberg

Crew on board the packed Boeing 777 became concerned when the captain did not respond to three requests to open the cockpit door. The first officer then entered the cockpit by an alternative method, which was not disclosed for security reasons.

Both pilots have been stood down over the incident and will be subject to additional training and counselling.