Labor is considering supporting the Morrison government's plan to fast track tax cuts for small and medium-sized businesses, boosting hopes legislation could pass parliament next week.

Under the plan, companies with annual turnovers of less than $50 million will have their tax rate cut to 26 per cent in 2020/21, then 25 per cent the following year.

Prime Minister Scott Morrison is confident of winning support for the plan, which would bring forward the cuts by five years at a cost of $3.2 billion.

"I'm going to legislate it next week, because small and family businesses deserve to have the support of this plan," he told the Seven Network on Thursday.

Labor leader Bill Shorten isn't ruling out supporting the proposal.

"We will keep an open mind on this question as we examine the numbers, but the other criteria we have is that our first priority is to properly fund our schools, to properly fund our hospitals," he told reporters in Brisbane.

Businesses turning over up to $50 million had their tax cut from 30 to 27.5 per cent last year.

The government had initially planned to implement further rounds of tax cuts in 2024/25 and 2025/26, but now wants to fast-track the plan.

Mr Morrison believes key crossbench senators who rejected the coalition's plans to slash tax for big businesses in August will back the step.

"Why would the Senate want to stand in the way of tax cuts for small, and medium-sized businesses? They voted for them before and they voted for them for the right reasons," he told the Nine Network.

The prime minister said the change won't affect the government's plan to return the budget to balance by 2019/20, followed by a more hefty the surplus the following year.

Mr Morrison is using the tax cut plan to highlight a policy difference with Labor ahead of the next election.

"It's a pretty clear contrast," he told ABC Radio.

"Labor's five point plan is tax, tax, tax, tax and tax."

The government claims the tax relief will benefit more than three million small and medium-sized businesses.

Shadow treasurer Chris Bowen is worried about the total cost to the budget.

"They are so desperate to throw cash at issues, whether it be small business tax cuts or other issues for their political purposes that they have thrown out their own budget rules," he said.

Australian Chamber of Commerce and Industry chief executive James Pearson said the move would be a major boost for small businesses.