Close to 64,000 New Zealand Facebook users have had their personal data accessed by Cambridge Analytica.

The social media behemoth is expected to notify 87 million users worldwide on Monday whose data may have been unknowingly shared with the British political consulting agency.

In New Zealand, Facebook estimates 10 people may have downloaded a quiz app, called "thisisyourdigitallife", possibly impacting 63,714 friends.

Any New Zealand users who might have had their data accessed by Cambridge Analytica would be notified by Facebook, a Facebook spokesman says.

The 2.2 billion Facebook users worldwide would also receive a message telling them to review the apps and websites connected to their account.

"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," a spokesman said.

About 310,000 Australian Facebook users have also had their data comprised.

Facebook has lost $100 billion of its sharemarket value since the Cambridge Analytica scandal broke three weeks ago.