The Australian and New Zealand militaries are monitoring three Chinese warships that are moving unusually far south along Australia’s east coast on an unknown mission.

Sailing in Australia’s exclusive economic zone, the three vessels were not breaking international law, but they were unusually far south on an undeclared mission.

Australia and New Zealand are monitoring a group of Chinese naval vessels spotted in international waters near Sydney, the countries’ defence ministers said on Thursday. Three Chinese vessels are traveling down the eastern coast of Australia,

Defence Minister Richard Marles says Australian ships and aircraft are working "very closely" with New Zealand's military to monitor a Chinese naval task force transiting south off the east coast of Australia, with the opposition labelling Beijing's behaviour "provocative."

Australian Minister for Defense Richard Marles labels it an “unusual event” as Chinese military ships traverse waters off Australia's coast. (Credit: Sky News)

Australian officials said the ships were "off the east coast of Australia" and their presence there was unusual.