Nearly 64,000 New Zealanders are estimated to have had their data collected and used by Cambridge Analytica, Facebook says.
A spokesperson for the social media giant said 87 million people were estimated to have been affected by the "Cambridge Analytica data misuse" worldwide, with more than 80 percent of those based in the US.
The data was apparently obtained via a personality test on Facebook and pulled in information about what their friends liked without their explicit permission.
"For New Zealand, we estimate a total of 63,724 people may have been impacted - 10 are estimated to have downloaded the quiz app with 63,714 friends possibly impacted," the company said.
The spokesperson said that from Tuesday the company would begin showing users which apps they connected to at the top of their Facebook feed, and an easy way to delete them.
"As part of this, we will let people know if their data might have been accessed by Cambridge Analytica," the spokesperson said.
"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."
Last month, Facebook acknowledged that personal information about millions of users wrongly ended up in the hands of Cambridge Analytica.
Cambridge Analytica is accused of selling the personal information of Facebook users to influence the US presidential election and the Brexit referendum.
The British-based consultancy has denied wrongdoing. It says it engaged a university professor "in good faith" to collect Facebook data in a manner similar to how other third-party app developers have harvested personal information.