Only 10 Kiwis are believed to have used the app behind the Cambridge Analytica data scandal.
But those 10 people exposed nearly 64,000 Kiwis' data, Facebook said on Monday.
Worldwide around 87 million people are believed to have had their data scooped up by the UK-based political data company, which used the information to target voters in the US election and Brexit vote.
People who used an app called 'thisisyourdigitallife' thought they were taking a personality test, but instead their information - and those of their friends - was being collected for political ad targeting.
This week, Facebook will be contacting those affected - including 63,714 New Zealanders - to let them know.
"We will begin showing everyone on Facebook at top of their News Feed the apps they have connected to and an easy way to delete them," head of communications for Australia and New Zealand Antonia Sanda said on Monday.
"As part of this, we will let people know if their data might have been accessed by [Cambridge Analytica]."
Facebook says it has been tightening up access apps have to users' data, including turning off access for apps that haven't been used in the last three months.
"Going forward, we're dramatically reducing the information people can share with apps. We're shutting down other ways data was being shared through groups, events, pages and search."
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Most of those affected live in the US, and would have been exposed to highly targeted advertising to sway them towards voting for Donald Trump in the 2016 election.
Around 300,000 Australians are also believed to have been affected.
If you, or anyone you know, has downloaded Cambridge Analytica please email shannonredstall@mediaworks.co.nz
Newshub.
