A Chinese state-sponsored group targeted New Zealand lawmakers in a hack in 2021, the New Zealand government revealed on Tuesday.
The announcement came after Britain and the US revealed that their democratic institutions and lawmakers had also been targeted.
"The use of cyber-enabled espionage operations to interfere with democratic institutions and processes anywhere is unacceptable," New Zealand Minister Responsible for the Government Communications Security Bureau (GCSB) Judith Collins said.
The hack had been attributed to a Chinese state-sponsored group known as APT40, Collins said.
New Zealand authorities had stopped the group from accessing the networks of two arms of the country's Parliament, she said.
"We commend the impacted organisations for acting decisively to mitigate the impact, and for the measures they have taken since the incident to harden their cyber defences and strengthen the resilience of their networks," she said.
"These networks contain important information that enables the effective operation of the New Zealand government. It is critical that we protect this information from all malicious cyber threats."
Accusing China of foreign interference was "completely barking up the wrong tree," the Chinese embassy said in a statement.
"We reject outright such groundless and irresponsible accusations and have lodged serious démarches to New Zealand's relevant authorities, expressing strong dissatisfaction and resolute opposition."
Cybersecurity was a global challenge, the embassy said.
"When investigating and determining the nature of cyber cases, one needs to have adequate and objective evidence, instead of smearing other countries when facts do not exist, still less politicize or even weaponize cybersecurity issues," it said.
"Non-interference in other countries' internal affairs is a fundamental principle of China's diplomacy. No one should do to others what they do not want done to themselves."
Earlier, New Zealand's Foreign Minister Winston Peters said concerns about cyber activity had been conveyed directly to the Chinese government.
"Foreign interference of this nature is unacceptable, and we have urged China to refrain from such activity in future. New Zealand will continue to speak out – consistently and predictably – where we see concerning behaviours like this," Peters said.
"We cooperate with China in some areas for mutual benefit. At the same time, we have also been consistent and clear that we will speak out on issues of concern," he added.