Australia learned about Chinese live-fire naval drills off the country’s coast that forced dozens of flights to be diverted via an alert from a commercial pilot, authorities said on Monday.

The Chief of the Defence Force, David Johnston, told Senate estimates on Wednesday that a warning from a New Zealand warship that Australia was relying on to track the flotilla was ­received in Canberra about 11am last Friday – 90 minutes after the exercise began and about an hour after a similar warning was ­relayed by a commercial pilot.

A Virgin Australia pilot alerted Australian authorities about a live-fire drill by Chinese naval ships last week in the Tasman Sea that forced 49 flights to change their paths, Australia's air traffic control agency head told a parliamentary committee.