The Senate has passed the first two stages of the Government's income tax cut plan.
It has rejected the final part of the plan, which would take effect in seven years and apply to high-income earners.
But the Government does not accept the bill being split and will insist on all three sections of the $144 billion tax plan being implemented.
When the bill is sent to the Lower House on Thursday, the Government will use its numbers to reinstate the third section.
"If it comes back here with the amendment, we'll send it straight back," Prime Minister Malcolm Turnbull said on Wednesday.
"We want all Australians to get the benefit of a comprehensive tax reform."
The third section would see the overwhelming majority of workers paying a marginal rate of 32.5 per cent from 2024.
There is likely to be a vote on the entire bill before the end of the week.
The Coalition will need One Nation's support, but the minor party has not declared its position.
"This is a real dilemma for me," leader Pauline Hanson said.
Senator Hanson indicated she wanted a multi-national tax avoidance crackdown in return for her support.
No point delaying a vote, Cormann says
Finance Minister Mathias Cormann moved a motion on Wednesday to force the Senate to vote on the amended tax bill tonight.
"We can have debate on this for another couple of weeks, it will not change the mind of the Labor Party, it will not change the mind of the Greens, it will not change the mind of Senator [Tim] Storer," Senator Cormann said.
"Everybody knows what their position is in relation to this bill."
Labor, the Greens and South Australian independent Senator Tim Storer all voted against the motion to curtail debate.
