The main political backers in support of the investigation into the future of journalism are no longer involved with the Senate committee, leading to a mass reshuffle of members and uncertainty about the future of the inquiry.

When the inquiry launched in May, to examine the structure of media organisations, tax arrangements and the increase of fake news, it was heavily backed by an alliance of senators - Scott Ludlam, Nick Xenophon, Sam Dastyari and Jacqui Lambie.

This alliance has now come apart.

Two months after the launch of the Senate committee, deputy chair Mr Ludlam resigned after finding he was ineligible to hold office after failing to renounce his New Zealand citizenship. Ms Lambie resigned later in the year after finding she was entitled to UK citizenship.

In October, member Mr Xenophon announced he would leave federal politics to head back to state politics in South Australia.