Finance Minister Mathias Cormann won't compromise on the coalition's signature income tax cuts plan, insisting the $158 billion package must go through parliament as a whole.
Senator Cormann is locked in negotiations with the Senate crossbench over the 10-year income tax relief plan.
He needs support from four of six crossbenchers to legislate the cuts in three weeks' time.
One Nation senators are demanding action on power prices and water storage in return for their support, while Centre Alliance senators want more help for pensioners.
Both minor parties, which each carry two votes, are apprehensive about the final phase of the three-stage plan, which would deliver tax cuts to high income earners.
"Obviously what individual senators say and advocate for is a matter for them," Senator Cormann told Sky News on Wednesday.
"What I can say from our point of view is that we absolutely will be putting forward the legislation to deliver on our entire plan for income tax relief.
"There is absolutely no chance at all that we will split off any part."
Labor backs the first stage of the cuts, for low and middle-income earners, but has doubts about the fairness and economic viability of the other stages.
