The New Zealand Security Intelligence Service is warning people to check what they share online after it was revealed a firm with ties to China's military has profiles on Kiwis of note.

Director-General of Security Rebecca Kitteridge that at this stage, the NZSIS believed the information found on the dataset had been mostly found through publicly available sources.

"While we are still assessing the information, at this stage we believe the information is primarily drawn from publicly accessible sources such as social media and news reporting," she said.

"We know that different organisations compile information of this nature from publicly accessible sources for a range of purposes, ranging from private companies wanting to carry out marketing or research at one end of the spectrum, through to governments seeking to influence public discussion or gather intelligence in other countries at the other."

Kitteridge said she understood that some people might've been unaware that information could be gathered up in this way, but it served as a warning.

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"This is a timely reminder to everyone to check the security settings on their social media accounts and review the amount of information they are sharing on the internet," she said.

The New Zealand Security Intelligence Service had the information relating to New Zealand and was reviewing it for any potential risks and security concerns, Kitteridge said.

New Zealanders form a small part of the dataset, which includes information on a very large number of people from a range of different countries and backgrounds, she said.

The Deputy Prime Minister earlier warned that "malicious actors" were exploiting Kiwis' private information after his daughter was targeted and tracked by a firm with ties to China's military.

The families of Winston Peters and other senior politicians — including Prime Minister Jacinda Ardern — have also been in the Chinese big data company's sights.

The sister and parents of Ardern have had profiles built on a secret Chinese database, along with the mother of former trade minister Todd McClay and one of ex-Prime Minister Sir John Key's children.

University of Canterbury professor Anne-Marie Brady, a specialist in China, said the revelations showed a concerted influence campaign from China targeted at political and business elites.

"Our New Zealand politicians are being targeted on a grand scale, and in minutiae,'' she said.