Shadow treasurer Jim Chalmers says Labor's highest priority is getting the first stage of the federal government's tax plan passed in the face of the slowest economic growth since the global financial crisis.
However, he continues to hold fire on supporting the full $158 billion tax package, $95 billion of which won't come into play until 2024.
The shadow cabinet will discuss the issue on Monday.
"We support sensible tax reform that prioritises middle Australia," Dr Chalmers told the ABC's Insiders program on Sunday.
Finance Minister Mathias Cormann jumped on the comment, saying it was good to hear Dr Chalmers supporting tax reform and a responsible budget.
"That's our plan," Senator Cormann tweeted.
"1) Tax cuts for low & middle income earners; then 2) Tax cuts for other working Australians: Phased in to be fiscally responsible."
Stage one of the plan is due to start on July 1.
"Our highest priority is to get money into the hands of workers, and flowing through an economy which desperately needs it," Dr Chalmers said.
He said the government's highest priority seems to be the third stage of the plan that doesn't come in for another five years.
"We want to know what that would mean for the budget and what that would mean for the economy, and the information that they don't want to provide us," Dr Chalmers said.
"It's a huge outlay of money ... so, I think that the Australian people expect us to get all of the information, to have the proper consultations and considerations before we come to a final view."
But the government has repeatedly rejected the idea of splitting the bill, which is expected to be high on the agenda when the 46th parliament sits for the first time after the federal election next month.
Assistant Treasurer Michael Sukkar said the tax plan - that also makes tax bracket changes down the track to tackle bracket creep - was widely canvassed throughout the election campaign.
"A plan like this all hangs together," Mr Sukkar told Sky News.
"The Labor party wants to cherry pick one or the other parts of the plan which they did before the election and they have been rebuffed by the Australian people."
The coalition claims it has a mandate to implement the tax plan in full because of its two-seat majority in the lower house but it still needs support from the crossbench in the Senate.
Reserve Bank governor Philip Lowe, who could pull the trigger on another interest rate cut when his central bank board meets on July 2, has urged parliament to use fiscal policy to help lift a slowing economy.
That includes tax cuts as well as increased infrastructure spending.
Business leaders, such as retail billionaire Solomon Lew, also want the tax plan passed by parliament, saying relief is needed now to boost confidence rather than enduring the frustration of political point scoring.
