The package would drop the tax rate from 30 per cent to 25 per cent for all companies by 2026-27.
Labor and the Greens strongly oppose the plan, which would amount to around $65 billion in lost tax over the decade.
The government needs support from 9 of 11 Senate crossbenchers - they have Cory Bernardi, David Leyonhjelm, Steve Martin, Fraser Anning and three One Nation senators promising to vote for it.
The two remaining Nick Xenophon Team senators are opposed.
Prime Minister Malcolm Turnbull needs another two Senate votes - from Independents Tim Storer and Derryn Hinch - to execute his plan to extend a reduction of the company tax rate to 25 per cent for big businesses.
Independent senator Derryn Hinch says he is still unsure and sluggish wages are a major concern and need to be addressed.
He says companies could sign an agreement with the Australian Tax Office to guarantee wage increases as their tax rate came down.
United States president Donald Trump recently passed his own corporate tax cuts.
That has sparked warnings from the Government that Australia would miss out on potential foreign investment, that it would be drawn to a more profitable US market.
The Government's previous efforts to reduce the tax rate for all businesses to 25 per cent were blocked in the Senate, with only smaller businesses receiving a cut so far.
