Treasurer Scott Morrison insists the government must "keep going" with its economic plan including lower taxes for business.
The Turnbull government is weighing up, ahead of federal parliament resuming on August 13, how to get its plan for a 25 per cent tax rate for all-sized businesses through the Senate.
The coalition is four votes short, with crossbenchers Brian Burston, David Leyonhjelm, Cory Bernardi and Fraser Anning on board the full package.
One proposal put forward by another crossbencher, Derryn Hinch, is to deliver a cut to businesses with turnovers of up to $500 million, so the big banks are excluded.
However, doing so would mean losing at least the vote of Senator Leyonhjelm.
A number of crossbenchers have flagged the idea of bringing forward the 25 per cent rate for small and medium sized businesses which is currently due to start in 2026/27.
Mr Morrison said the government's strategy required competitive taxes for all businesses.
"This is part of the Turnbull government's plan for a stronger economy that is getting results," he told reporters in Melbourne on Thursday.
Workplace Minister Craig Laundy talked down any compromise.
"The problem you've got is it creates complication inside the actual tax bracket," he told Sky News.
"The second problem is it provides ultimately a disincentive for small and family businesses to grow as they get close to whatever turnover figure you desire.
"That's why we've been so strong on the fact that it's for business irrespective of size."
Liberal frontbencher Michael Sukkar said there was a global imperative.
"What Bill Shorten is essentially saying is every Australian company will compete against international competitors with one arm tied behind their back," Mr Sukkar said.
"How on earth can we have tax rates that are much higher than any of our competitors without it having some sort of impact on our prosperity and investment in this country?"
Labor argues corporate tax cuts take money from schools and hospitals and hands it to the big banks - a line that hurt the Liberal vote in two recent by-elections.
The Council of Small Business says the 25 per cent rate should start on July 1, 2020 as an incentive for investment.
Senator Leyonhjelm said while speeding up the rate rollout would be worthwhile, he would not vote for any further "tax discrimination" based on another turnover threshold.
Labor, the Greens, One Nation, Centre Alliance and independent Tim Storer do not support any further cuts.
