Australia's privacy commissioner has launched an investigation into Facebook after the social media giant revealed that the data of 311,000 Australians may have been "improperly shared" with data science firm Cambridge Analytica.

Federal MPs are holding off from any further action – such as a parliamentary inquiry similar to those occurring in Britain and the US – until the privacy commissioner and a separate Australian Competition and Consumer Commission inquiry have finished their work.

As part of its effort to address a global backlash triggered by the Cambridge Analytica scandal, Facebook announced on Thursday that 87 million users globally may have been affected, far more than previous estimates of 50 million and Cambridge Analytica's own claim of 30 million.

Facebook chief executive Mark Zuckerberg.

The acting Australian Privacy and Information Commissioner, Angelene Falk, confirmed her office would now probe whether Facebook had breached privacy laws, which require businesses to take reasonable steps to secure personal information and be transparent about the collection and handling of data.