The proposed fine is the largest issued by the Information Commissioner's Office (ICO) and the maximum allowed under the 1998 Data Protection Act, which applied at the time of the breaches.
Under Australian law, all organizations must take "reasonable steps" to ensure personal information is held securely and IMF Bentham has teamed up with a major law firm to lodge a complaint with the Office of the Australian Information Commissioner (OAIO).
Damian Collins MP, the chair of the Digital, Culture, Media and Sport Committee that has been investigating Cambridge Analytica, said: "Given that the ICO is saying that Facebook broke the law, it is essential that we now know which other apps that ran on their platform may have scraped data in a similar way".
The survey results were allegedly used by election consultants Cambridge Analytica to target voters in United States elections, including Donald Trump's presidential campaign.
The report sets out regulatory action taken against a number of the star players in this year's data scandal, including a criminal prosecution against Cambridge Analytica's parent biz SCL Elections Ltd - which has since folded, in name at least - for failing to properly deal with the ICO's enforcement notice.
"A significant finding of the ICO investigation is the conclusion that Facebook has not been sufficiently transparent to enable users to understand how and why they might be targeted by a political party or campaign", Denham wrote, according to the Post.
Facebook has said it will be reviewing the report and responding to the ICO soon.
"This can not by left to a secret internal investigation at Facebook". The U.K.'s investigation found "evidence that copies of the data/parts of it also seem to have been shared with other parties and on other systems beyond", which "potentially brings into question the accuracy" of Cambridge Analytica's assertion that it wiped the data from its stores.
"Facebook should now make the results of their internal investigations known to the ICO, our committee and other relevant investigatory authorities".
Politicians are calling for greater transparency from Facebook in light of the ICO fine.
It also said it would send warning letters to 11 political parties to compel them to audit their data protection practices.