Liberal senator Cory Bernardi is set to split from the Coalition over coming days to form his own political party.
The ABC understands the South Australian senator will walk out of the Liberal Party within the next 48 hours.
Senator Bernardi has previously indicated he may start a new party for disenchanted conservative voters, with reports surfacing as early as mid-2016.
In July he called for voters to back his Australian Conservatives movement, citing the need for a “broad conservative movement to help change politics”.
Federal Parliament returns on Tuesday and it's expected that a statement to the Senate will be the first the public hear from Senator Bernardi on his departure from the Coalition.
In his latest newsletter, Senator Bernardi foreshadowed a "testing year" for the Government.
"Unfortunately there are too few in our body politic willing to take the path less travelled — a trustworthy track that has fallen out of use," he said.
"For the sake of our nation, we must get back on track."
Bernardi frustrated by politically correct party leaders
The South Australian senator is a social conservative and economic liberal — he believes in small government, lower taxes and free trade, and thinks the Coalition has drifted from these values.
After the July election, Senator Bernardi lamented the fact that the Coalition had "bled" more than a million votes to conservative parties such as One Nation, and said at the time his party was neglecting its base.
— ABC News (@abcnews) February 5, 2017