A geopolitical expert says it's a good thing a New Zealand navy ship was on its own in waters around East Asia - when it was shadowed by seven Chinese warships.

The vessel was patrolling last month as part of international efforts to monitor and restrict North Korea’s nuclear and missile activity.

The Defence Force says the Chinese ships followed at a safe, professional distance.

Geoffrey Miller told Ryan Bridge we'll have to wait and see if there are further repercussions.

He says China's usually more offended by joint actions with other Five Eyes countries - so it's probably better our Defence Force was alone.

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