The tax changes, which will limit negative gearing on properties to new homes from July 2027 and scrap a 50 per cent discount on the capital gains tax for a rate tied to inflation, passed the House of Representatives on Thursday.
The bill will be voted on in the Senate after a rapid-fire inquiry examining the tax overhaul later in June.
The passage of the laws remains unclear, as the government needs support from the Greens to get the changes through.
Opposition Leader Angus Taylor said the coalition, which have already come out against the tax changes, were willing to work with the Greens on voting down the measures.
"We'll work with anyone to stop toxic taxes ... we'll work with whoever we can," he told reporters in Canberra on Thursday.
"The Greens have an opportunity here to stop this legislation, and we'll work with whoever we can to stop this toxic legislation getting through the parliament."
Greens senator David Shoebridge has expressed reservation about discretionary powers contained in the laws which could allow for ministers to make changes to some of the provisions after the laws were passed.
"Traditionally, they're called Henry VIII powers, and that didn't go well for parliament at the time," he told Sky News.
"It's a real issue for us that the government has put a secret backdoor in their legislation to undermine any of the very minor changes that they're putting to tax wealth, and it's a significant issue for us."
Treasurer Jim Chalmers said the Greens' concerns were a beat up and Labor was still consulting with the party about the tax changes.
"This is standard practice for tax legislation. We've seen it under governments of both political persuasions," he told reporters in Canberra.
"(The Greens) intend to raise (issues) at the senate committee over the course of the next couple of weeks, and that's appropriate as well. But this is standard practice for tax legislation."
Treasury secretary Jenny Wilkinson, appearing before a senate budget inquiry said parliament would be able to stop any future changes to the laws
"These are disallowable instruments, and they need to be consulted on," she told the inquiry.
Finance Minister Katy Gallagher told the inquiry the laws had not been changed to take into account any large exemption in the future.
Independent senator David Pocock has called for the government to split up the government's bill so tax offsets can be passed quickly.
The contentious tax changes have also been lumped in with laws setting up a $250 a year tax offset for working Australians, as well as $1000 instant deductions when people are filing their annual return.
Senator Pocock said more scrutiny was needed on the negative gearing and capital gains changes.
"The case hasn't been made, and the details haven't been sorted out, and it's not good enough for a government to basically say let's ram this through parliament and the treasurer will just make rules down the track and sort things out," he said.
