Incoming senator Jacqui Lambie under the pump to pass tax cuts

The Morrison government will try to push its $158 billion tax cuts through Parliament as early as possible this week when MPs return to Canberra, setting up a potentially awkward rush for new independent senator Jacqui Lambie, on whom the vote will hang.

With Parliament returning for the first sitting week since the federal election, the government aims to have the package through the lower house on Tuesday night, after which it will go to the Senate.

Key Senate crossbench party the Centre Alliance have strongly indicated they will support all three phases of the tax cuts, meaning the government needs only Ms Lambie’s vote.

The newly elected Tasmanian, who will be sworn in on Tuesday morning, doesn’t yet have staff on her payroll and therefore will have barely 48 hours to digest the detail of the legislation with the help of advisers. Ms Lambie’s office did not respond to requests for comment on Saturday.

But an informed source said: "Jacqui will no doubt have been taking some soundings, so it’s not as if, come Monday, she walks in cold. She just won’t have had the ability to rely on advisers, so she is on three of her eight cylinders."

The tax cuts are set to dominate the first week back for MPs along with the swearing in of new governor-general David Hurley and condolences for former prime minister Bob Hawke.

The introduction of laws to prevent religious discrimination will have to wait until the next sitting period later in July.

Incoming senator Jacqui Lambie will be up against the clock deciding this week whether to support the Morrison government's tax package.Credit: Janie Barrett

Crucially, Ms Lambie is part of a loose voting bloc with the Centre Alliance’s two senators, suggesting she is inclined to support the tax cuts, though the Centre Alliance has stressed that they will only co-operate when there is common ground.

The government’s goal is to have the package through both houses by the time the Senate rises on Thursday night.

Labor is expected to move amendments to the tax cuts package in the House of Representatives on Tuesday but, assuming those are rejected on party lines, could still back the package unamended in the Senate, especially if it believes the package will get through anyway on crossbench support.

Opposition Leader Anthony Albanese reiterated on Saturday that Labor supports phase one of the government’s tax package and wants to fast-track phase two, but still has doubts about phase three, which wouldn’t start until 2024-25.

Prime Minister Scott Morrison is pressuring Labor to pass the full tranche of tax cuts.Credit: AAP

"Our whole point here is we don’t know what the economy will look like in five years’ time," he said.

Stage one means most workers get a $1080 tax cut in their tax return in July. Stage two will see that benefit double from 2022-23.

Under the more controversial stage three, which introduces a flat rate of 30 per cent on incomes between $40,000 and $200,000, the largest benefits will go to higher income earners because they pay more tax.

Centre Alliance senator Rex Patrick said on Saturday that his party’s concern that the tax cuts would be eaten up by rising household power prices had been assuaged by the government’s promise to introduce measures to lower gas prices.

"I think there’s a reasonable chance we can get to a point where we can support the tax cuts."

He said he was happy to accept the government’s assurance that the gas measures would happen.

He praised Finance Minister and government Senate Leader Mathias Cormann as someone who "operates with integrity", though he added pointedly that if the government were to break its word so early in the parliamentary term, Senator Cormann would "find himself in a really tricky situation moving forward" with the next negotiation.