Australia’s defence minister Peter Dutton has accused China of committing an “act of aggression” after a People’s Liberation Army naval vessel came within 50 nautical miles of a naval communications centre.

Australia’s department of defence said the Dongdiao Class intelligence ship Haiwangxing had entered the country’s exclusive economic zone, which extends 200 miles to sea, and been monitored over the past five days. The vessel hugged the western Australian coastline and sailed close to Exmouth, where a cluster of radio towers is located at a naval base that is used by the US and other allies’ submarines, and was now travelling north-east.

Dutton said it was “unusual” that Australian authorities had not been informed about the ship’s course and that it was “unprecedented” that a Chinese vessel had headed so far south.