The Turnbull government will commit $100 million to secure private investment in greenfield mineral exploration across the country to drive a new wave of discoveries and restart the flagging mining sector in its west.

WA had been the biggest beneficiary of the once-in-a-century mining boom during the first decade of the 2000s and into the start of this decade, but has become the country's worst-performing economy as mining investment abated.

Prime Minister Malcolm Turnbull at the WA Liberal State Conference in Perth on Saturday. Credit:AAP

The poor economic outlook and gripes over WA's share of GST income saw the state's opposition this week discuss a "WAxit" option to break from the Commonwealth of Australia.

Speaking at the Western Australian Liberal Party conference in Perth on Saturday, Prime Minister Malcolm Turnbull announced new tax incentives for junior exploration companies in a move he said would encourage investment and "risk taking".