Big social media companies know more about you than your friends do and in some cases they are letting that data fall into the wrong hands, national cyber security adviser Alastair MacGibbon has warned.

Key points: Privacy Commissioner's office will ask Facebook if Australians' data has been used

Privacy Commissioner's office will ask Facebook if Australians' data has been used Cambridge Analytica allegedly helped Donald Trump win the 2016 US election

Cambridge Analytica allegedly helped Donald Trump win the 2016 US election British documentary revealed techniques executives said they would use to influence elections

The Privacy Commissioner is already investigating whether any Australians have been caught up in an international scandal about the misuse of Facebook profiles.

Political research firm Cambridge Analytica is accused of mining the data of 50 million users around the world, and using it to target people with political advertising aimed at helping Donald Trump's 2016 US election campaign.

Mr MacGibbon said he is not greatly surprised by the fact that data has been potentially misused.

He told ABC News that tightening privacy settings on individual Facebook accounts would do nothing to prevent the big internet companies harvesting personal data.

Mr MacGibbon said having strict privacy controls would mean that other people could not get access to their information, but "the company sees everything".

"These big internet companies know more about us than most of our friends know about us," he said.

"If you are a search company they know your behaviours and interests, if you are a social media company, they know your friendship groups and your behaviours."

The Cambridge Analytica scandal poses a new risk to Facebook's reputation. ( Reuters: Dado Ruvic )

Mr MacGibbon said the big internet companies make billions of dollars of profit by providing a free service and then using the data and "in some cases clearly allowing that data to get into the wrong hands".

The Privacy Commissioner's office has asked Facebook if the data of any Australians was acquired and used without authorisation to build profiles that political parties could use to target voters.

The Commissioner said any penalties would range from regulatory action to court-imposed penalties.

"My office is making inquiries with Facebook to ascertain whether any personal information of Australians was involved," the Commissioner said in a statement.

"I will consider Facebook's response and whether any further regulatory action is required."

Facebook had its worst trading day in five years following the accusations against Cambridge Analytica, with about $US35 billion ($45.38 billion) wiped off its total market value on Monday (US time).

Australia named as possible next target

Sorry, this video has expired A former Cambridge Analytica employee says the firm used "information dominance" to spread fake news

A Channel 4 documentary aired in the UK on Monday inflamed the debate around the consultancy firm.

The documentary used hidden cameras to film Cambridge Analytica executives describing their use of techniques to influence elections, ranging from using big data and perception manipulation to setting honey traps for opposing candidates.

In the footage, the firm's chief executive, Alexander Nix, described capturing compromising video of opposition candidates.

"We'll have a wealthy developer come in, somebody posing as a wealthy developer," Mr Nix said in the footage.

"They will offer a large amount of money to the candidate, to finance his campaign in exchange for land, for instance.

"We'll have the whole thing recorded on camera, we'll blank out the face of our guy and then post it on the internet.

"Send some girls around to the candidate's house. We have lots of history of things … we could bring some Ukrainians in … they are very beautiful, I find that works well."

The investigation also revealed executives talked about working in Australia.

"We've done it in Mexico, we've done it in Malaysia, we're now moving into Brazil, Australia, China," Cambridge Analytica's managing director of political operations Mark Turnbull said in the video.

The ABC's PM program contacted the federal Labor and Liberal parties to ask if they used or considered using Cambridge Analytica.

The Labor Party ruled out working with the company. A Liberal spokesman said the party did not and had not used its services.

But Liberal MP Dan Tehan's office confirmed he attended a private dinner with Cambridge Analytica executives last year.

Cambridge Analytica CEO Alexander Nix (right) had his conversation recorded by hidden cameras. ( Supplied: Channel 4 )

'Company took fake news to next level'

Adding to the pressure on Cambridge Analytica, Britain's information commissioner said she would apply for a warrant to access the company's servers.

The company has rejected the allegations made in the Channel 4 report, saying it was "edited and scripted to grossly misrepresent the nature of those conversations and how the company conducts its business."

Cambridge Analytica also tweeted on Tuesday night: "No Facebook data was used by our data science team in the 2016 presidential campaign."

The scandal erupted when former Cambridge Analytica employee Chris Wylie blew the whistle on the company, telling The Guardian it "exploited Facebook to harvest millions of people's profiles ... and build models to exploit what we knew about them and target their inner demons".

He told CNN he played a significant role in setting up the company and felt like it was his duty to tell people what it did.

He claimed the Cambridge Analytica scandal was a case of "informational dominance", the idea that if a person is surrounded by certain content, their perception of what is actually happening can change.

He told NBC News Today Cambridge Analytica was born out of the SCL Group — a military contractor based in London.

He said it set out to explore people's "mental vulnerabilities" and then "map out ways to inject information into different streams or channels of content online so that people started to see things all over the place that may or may not have been true."

"This is a company that really took fake news to the next level by pairing it with algorithms."

If anyone has concerns about how their personal information has been collected or managed, they can get in touch with the office of the Australian Information and Privacy Commissioner by visiting www.oaic.gov.au or calling 1300 363 992.



ABC/wires