A New Zealand navy ship's been shadowed by seven Chinese warships in East Asian waters.  

HMNZS Aotearoa was carrying out surveillance and deterrence activities last month to enforce the UN's sanctions against North Korea.   

The Defence Force has confirmed the warships kept a safe distance throughout. 

Otago University international relations professor Robert Patman told Heather du Plessis-Allan it indicates China firmly believes in its sovereignty over the Taiwan Strait. 

He says a growing consciousness of military might means China's less tolerant of infringements on what it sees as its sovereign claim. 

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