Scott Morrison’s government is ramping up pressure on Labor to back its full $158 billion package of tax cuts, as the clock runs down on its campaign to get the plan through federal parliament.

But the opposition wants to see whether Senate crossbenchers green light the cuts before declaring how it will vote.

The coalition needs the support of Labor or four out of six crossbenchers to push the three-stage plan through the upper house after parliament resumes this week.

So far Labor has refused to back the full plan, offering to support extra tax relief only if the second stage of the package is brought forward and the third stage is shelved.

The coalition has given no ground, saying it won’t split the bill.

Labor frontbencher Katy Gallagher said the party will consider its position on the package when its caucus meets early this week.

“We would have to take decisions based on what was happening at the time,” Senator Gallagher told Sky News on Sunday.

The prime minister has vowed to use all options at his disposal to get the tax cuts through parliament.

“We want them passed this week … and we will use every procedural option to achieve it,” he told The Australian in Osaka after the G20 summit.

Treasurer Josh Frydenberg, meanwhile, has penned an opinion piece in the same paper, arguing Labor’s position shows it’s the party of “higher taxes”.

He has also accused it of continuing to raise excuses for not backing the tax cuts, including “it’s best excuse yet: that it can’t take a decision until it sees what the crossbench does”.

“In other words, Labor can only vote for it, if it can’t oppose it,” Mr Frydenberg wrote.

The first stage of the plan will deliver up to $1080 to low and middle-income earners when they lodge their tax returns in the coming months.

The second stage will top-up a low income tax offset which means more people – earning up to $45,000 instead of $41,000 – will get a 19 per cent tax rate.

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.

Left-leaning think tank The Australia Institute says there should be a Senate inquiry into Labor’s concerns that the third stage may be unaffordable for the budget in five years time.

So far the only crossbench senator to have backed the government’s plan is former Liberal Cory Bernardi.

Two Centre Alliance Senators have been been in talks with the government about measures to keep gas prices low to ensure the extra tax relief won’t be chewed up by power bills.