The New Zealand government says 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. "We are aware of 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. Sailors on the New Zealand Navy frigate Te Kaha observed live rounds being 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". New Zealand Prime Minister Christopher Luxon said earlier on Saturday it was unclear where the Chinese naval vessels were headed in international waters, and for what purpose. Saturday's live-fire drill took place in the Tasman Sea, broadcaster Radio New Zealand reported. On Friday, airlines including Qantas, Emirates and Air New Zealand had to modify flight paths between Australia and New Zealand after China broadcast a message that its navy would hold live-fire exercises in international waters off the NSW coast. Defence Minister Richard Marles said on Saturday Beijing had failed to give satisfactory reasons for what he called inadequate notice of Friday's live-fire drill. "We weren't notified by China, we became aware of the issue during the course of the day," he told ABC Radio Perth. Chinese foreign ministry spokesman Guo Jiakun said China had followed international law. "The drill was carried out in a safe, standard and professional manner in accordance with the relevant international law and international practice," he said. The live-fire drills took place after a People's Liberation Army Navy frigate, cruiser and replenishment vessel entered Australia's maritime approaches last week and travelled down the east coast this week, monitored by both the Australian and New Zealand militaries. Earlier this month, Australia also complained about "unsafe and unprofessional" actions by a Chinese fighter jet towards an Australian maritime patrol in the South China Sea. Beijing accused the Australian aircraft of "deliberately intruding" into its airspace. China rejects a 2016 ruling by the Permanent Court of Arbitration in the Hague that its claim to almost all of the South China Sea, parts of which are also claimed by several South-East Asian nations, is not supported by international law.