Morrison tax plan in hands of crossbench

THE Morrison government is closer to finding out whether it has convinced minor party Centre Alliance to back its full $158 billion tax plan.

The government needs the votes of four of the six Senate crossbenchers to get its three-stage package through the upper house when parliament returns next week.

Labor backs stage one of the plan and wants to bring stage two forward but has not yet offered the final stage its support.

"We're the only party arguing at the moment for every worker - whether they're on $45,000 or $200,000 right now - should get a tax cut in this term," Opposition Leader Anthony Albanese told Sky News on Thursday.

"The only people threatening to exclude anyone from getting a tax cut is the government because of the political way they are handling this."

The government has flatly rejected splitting up its tax package.

The final stage will flatten the tax rate from 32.5 per cent to 30 per cent for people earning between $45,000 and $200,000 from mid-2024.

Finance Minister Mathias Cormann says this will "take the bracket-creep monkey off all Australian workers".

"We call on all parties in the parliament to demonstrate goodwill and facilitate speedy passage of that very important piece of reform legislation," he told reporters on the sidelines of the G20 summit in Japan.

Centre Alliance, which controls two votes, has been negotiating with the government on measures to reduce gas prices to ensure the extra cash some Australians will get won't be chewed up by rising power bills.

Senator Rex Patrick says negotiations are days from ending.

"The devil is always in the detail and we are still working through the detail," he told AAP.

"We anticipate a package of solutions which include both long and short-term options."

Senator Cormann was not able to confirm what measures are being discussed.

"Consistent with our usual practice, we will not provide a running commentary on every proposal or suggestion that is publicly promoted by individual non-government senators," he told AAP.

It is expected the Senate will be asked to back a procedural motion next week which will clear the decks for a debate on the tax bill immediately after the lower house passes it, in a bid to get parliament's nod quickly.

So far the only crossbencher to back the coalition's full tax plan is Senator Cory Bernardi, a former Liberal.

One Nation, which holds two seats, has vowed not to support the plan, while Senator Jacqui Lambie hasn't declared her hand.

The Greens, who control nine votes, are opposed.

The first stage of the plan will mean extra cash for low and middle-income earners in coming months.

Labor will only support the second stage that is due to kick in from 2022/23 if the government brings it forward to the coming financial year.

This stage will top-up a low income tax offset and mean more people - earning up to $45,000 instead of $41,000 - will get a 19 per cent tax rate.