WELLINGTON, New Zealand - New Zealand on Tuesday blamed "state-sponsored" Chinese hackers for a "malicious" 2021 cyber attack that infiltrated sensitive government computer systems.

The country's counter-espionage agency said a state-backed group known as "APT40" compromised computers linked to its parliamentary network.

The announcement comes on the back of similar claims unearthed in the United Kingdom, which overnight accused Beijing-linked groups of compromising parliamentary accounts.

New Zealand security services minister Judith Collins said they were able to attribute the attack following a "robust technical assessment".

"These networks contain important information that enables the effective operation of the New Zealand government," she said in a statement.

"It is critical that we protect this information from all malicious cyber threats."

APT40 has previously targeted "governmental organizations, companies, and universities in a wide range of industries", according to the US government's Cybersecurity and Infrastructure Security Agency.

Attribution of sophisticated cyberattacks is both technically difficult and politically fraught -- and is likely to anger China.

China's ambassador to London will be summoned "to account for China's conduct", UK Deputy Prime Minister Oliver Dowden said, while Foreign Secretary David Cameron said he had raised the issue with his counterpart Wang Yi.

Wang recently wrapped up a rare diplomatic jaunt to New Zealand, where he stressed the need to work alongside "friends".