New Zealand said the Chinese navy conducted a live-fire exercise in international waters near the Pacific nation on Saturday, a day after it held a similar drill between Australia and New Zealand that forced airlines to divert flights.

"Reporting from the New Zealand Defence Force that the Chinese naval Task Group has advised of a second window for live firing activity, on Saturday afternoon," a spokesperson for Defence Minister Judith Collins said in a statement.

Personnel on New Zealand Navy frigate Te Kaha observed live rounds fired from a Chinese vessel's main gun, the statement said, adding that the task group had "advised via radio channels of its intent to conduct live firing."