Photo: 123rf
Security agencies say it is hard to tell if their warnings about an "urgent risk"' of Chinese cyber attacks on important infrastructure have made a difference.
The government has accused Beijing of being behind a hack Parliament three years ago, a charge it rejects.
Separately, Western agencies have been warning for weeks that China has "successfully compromised" critical infrastructure in the US especially in the communications, energy, transport and water systems.
The National Cyber Security Centre (NCSC) signed the latest warning last week, and told RNZ on Wednesday it was not aware of direct impacts in New Zealand.
"This activity relates to a sophisticated state actor and detecting such activity is challenging," it said in a statement.
"While we are not aware of direct impacts in New Zealand from this activity, New Zealand critical infrastructure operators often use similar technology and systems to those utilised in the United States."
The attacks in the US have been blamed on Volt Typhoon, and other hacker groups China is accused of backing.
The US this week sanctioned China-based hackers for allegedly targeting its infrastructure, and the UK joined in.
The US and UK accuse China of a years-long cyber-attack campaign. China responded that it is the victim of hacking from the West.
On Wednesday, the collapse of a bridge in Baltimore after a ship rammed it, led to a flurry of conspiracist posts online including blaming a cyber attack, but the White House said there was no indication of "nefarious intent".
New Zealand has stopped short of sanctions.
Foreign Minister Winston Peters said he conveyed concerns to the Chinese Embassy on Tuesday about the hacks at Parliament in 2021.
Asked by RNZ if he included Volt Typhoon in those concerns, a spokesperson for Peters said in a statement: "Regards to Volt Typhoon, the NCSC joined with partners in February in publishing guidance and also identifying state actors including the PRC.
"As you're aware, our most recent interaction with PRC prior to the call to the Chinese Ambassador, was the visit by Foreign Minister Wang Yi. While we will not go into specifics ... New Zealand's concerns about malicious cyber activity in general were raised with China by officials earlier this month, as they have previously."
The Volt Typhoon advisories in February and March preceded the government on Tuesday for the first time accusing China of targeting this country's parliamentary systems. This followed the UK making a similar charge overnight on Monday.
The NCSC said its advisories often shared "critical" information with operators.
"By alerting them to the type of activity referred to in the Volt Typhoon advisory, we hope to equip organisations to respond if they suspect or observe this behaviour," it said.
A security threat environment report last year for the first time publicly named China - as well as Russia and Iran - as carrying out foreign interference in New Zealand.
Officials, in their initial briefing to Prime Minister Christopher Luxon as national security and intelligence minister, said one priority in their first three months would be advising him on improving critical infrastructure resilience.
China's growing economic, political, and military power, and "more assertive pursuit of its interests abroad", were key drivers of "strategic competition" that was a threat to New Zealand's national security interests, the briefing to Luxon said.
It was affecting foreign interference, economic security, Pacific resilience and security, it said.
In early February, the FBI said it had disrupted Chinese attempts to put malware into water treatment plants, the electrical grid and transportation systems.
