Cory Bernardi is set to upend centre-right politics in Australia and announce on Tuesday that he is resigning from the Liberal Party to head his own conservative movement in a stunning move that will rock the Turnbull government as Parliament returns for the new political year.

Fairfax Media has learnt that in recent days Senator Bernardi informed his staff of his decision to defect from the party he has represented in the Senate for a decade. He will join the crossbench as an independent conservative senator for South Australia, fearing that populist parties will continue to rise if right-wing voters aren't given a viable alternative.

It's understood Senator Bernardi will phone Prime Minister Malcolm Turnbull in the morning, before delivering his resignation to the Senate after midday.

His resignation will emulate Don Chipp's in 1977, when the former Liberal minister sent shockwaves through the Coalition by quitting the party and founding the Australian Democrats. There are now fears other MPs could follow Senator Bernardi out the door, along with Liberal Party donors and voters. The outspoken conservative Nationals MP George Christensen has previously said he would use the summer break to also consider his future but has so far ruled out a switch.