Malcolm Turnbull's company and personal income tax cut plans look to be in trouble.
The prime minister was forced to defend his 10-year business tax cut plan in parliament on Tuesday after Pauline Hanson withdrew her One Nation senate team's support.
Senator Hanson reeled off a number of reasons for reneging on an agreement while saying she felt the government had not addressed a "black hole" in the budget.
With other crossbenchers and Labor opposed to the plan, the government needs Senator Hanson and her two One Nation colleagues' votes to help secure the package.
Parliamentary debate also started on the government's seven-year personal income tax plan, the cornerstone of this year's budget.
Labor wants the bills split so it can support the reductions that are due to start on July 1 because it still has reservations about a proposed reduction in 2022 and 2024 in the absence of further details.
The government has repeatedly said it wants the package passed in full.
The opposition supports the reduction of up to $530 a year under a new low and middle-income tax offset and the lifting of the 32.5 per cent tax bracket from $87,000 to $90,000, both starting on July 1.
One Nation does not support the personal income tax cut in 2024 either, saying Australians needs their tax cuts now.
The Greens won't support any income tax cuts or Labor's compromise and instead want the money invested in the nation's public services.