Facebook said they will let users know if they think their data may have been accessed by Cambridge Analytica.

New Zealand's privacy commissioner has requested more information from Facebook about what 63,724 compromised accounts in New Zealand may have been exposed.

Facebook revealed on Monday that just under 64,000 New Zealanders' accounts may have been affected by Cambridge Analytica's data "misuse" of 87 million people's data globally.

Of the Kiwis possibly affected, 10 are estimated to have downloaded the personality quiz app, thisisyourdigitallife, that facilitated the breach – possibly impacting thousands of their friends accounts, Facebook spokeswoman Antonia Sanda​ said.

STUFF Privacy Commissioner John Edwards says Facebook users should examine their use of the social media platform after it failed to comply with New Zealand law.

Three million New Zealanders have Facebook accounts.

Did you downloaded the thisisyourdigitallife app? Email madison.reidy@stuff.co.nz

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MARCIO JOSE SANCHEZ/AP Of the Kiwis possibly affected, 10 are estimated to have downloaded the quiz app involved, with 63,714 friends possibly impacted, Facebook said on Monday.

Commissioner John Edwards said "goodness knows" what advertisements or apps the compromised accounts had been exposed to on the social media platform since 2015, when the app was deployed.

Data firm Cambridge Analytica used information about Facebook users' personalities and allegedly used it to target users with political propaganda during the 2016 United States general election and Brexit referendum.

The third-party app also gathered information on the Facebook friends tied to the accounts who downloaded the app, without their authorisation.

Edwards said he did not know what New Zealanders' information could have been used to manipulate.

"I have no better idea that anyone. There has been some manipulation of people's news feeds. The scope to misuse is pretty wide."

He had not decided to investigate the case; however, he was interested in speaking to the 10 people who downloaded the app to ask what they had seen on their news feed, he said.

FACEBOOK/SUPPLIED Facebook released the number of people whose information may have been improperly shared with Cambridge Analytica last week. It did not include the number of New Zealanders.

Edwards was not surprised that New Zealand accounts were caught up in the Cambridge Analytica scandal, but he was "astounded" that thousands of accounts were affected by only 10 downloads of the compromised app.

Facebook was "a little bit slow" to take action against Cambridge Analytica and its parent company SCL; however, he could not condemn the actions taken since it found out about the United Kingdom-based firm's intentions.

Facebook banned the thisisyourdigitallife app last month when a former Cambridge Analytica employee blew the whistle on its data mining purposes.

Sanda said every user whose information was possibly compromised by Cambridge Analytica would be notified by Facebook.

"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. As part of this, we will let people know if their data might have been accessed by CA."

Experts suggest that Facebook users concerned about their privacy start by switching off Facebook's access to your GPS location in "settings," to keep your daily movements private.

They also suggest changing who can see your posts to the "Only Friends" setting in account settings.

Facebook announced last week that 87 million Facebook accounts could have been compromised. More than 80 per cent of those accounts were in the United States. More than 311,000 of them were in Australia.

It reached those numbers by calculating the maximum possible number of friends lists that every person who downloaded the thisisyourdigitallife app could have had since 2015, Facebook founder Mark Zuckerberg said on a media conference call last week.

"It very well could be less, but we wanted to put out the maximum we felt that it could be."

He admitted the technology giant did not do enough to protect users from third party apps. It had begun auditing every third party app with suspicious activity, a process Zuckerberg said would take years.

"This is going to be a never ending battle. You never fully solve security, it's an arms race," he said.

Last month Edwards named and shamed Facebook after it did not comply with his investigation into a complaint.

Facebook refused to give the complainant and Edwards access to personal information held on the accounts of several Facebook users.

Facebook defended its decision. It said it did not have to abide to New Zealand law because its New Zealand operations were headquartered in Ireland.

Edwards said by denying him access to information, Facebook had "fundamentally failed" to follow New Zealand laws. He had no power to prosecute Facebook.

Zuckerberg said Facebook had 15,000 staff working on reviewing and tightening the platform's security measures. It would hire another 5000 by the end of the year.

"This is an important area of work for us," he said.

In a statement released last month, the company announced several ways it would crackdown on third party apps.

Those changes included turning off an apps access to a person's profile if they did not use it for three months.

Apps that wanted information from a user other than their name, profile photo and email address would need to be granted approval by Facebook to do so.

Facebook has a bug bounty program where it pays rewards to people who report security issues on Facebook or any of its acquired apps such as Instagram and WhatsApp.

Last year it paid more than US$6,300,000 (NZ$8,657,460) in bounty rewards.﻿