Federal Greens leader Adam Bandt revealed on Sunday his party would support Labor's Housing Australia Future Fund (HAFF) legislation, on the condition the government tackles immediate rental stress and commits $2.5 billion a year to purchase existing properties for social housing.
The new demands are similar to the Greens' original position but come at roughly half the cost to the government.
"If Labor backs a rent freeze and guarantees real money for more housing, the Greens will pass Labor's bill," Mr Bandt said.
"The Greens have shown we can negotiate with Labor and get significant outcomes for people and the climate.
"We're now trying to fix the broken HAFF Bill, but Labor has to shift."
The $10 billion HAFF aims to build 30,000 new social and affordable housing properties in the first five years of its existence and deliver returns to back further social housing projects.
The Greens say the plan won't produce any new social housing for at least several years and are insisting on immediate steps to tackle the housing crisis facing many Australians.
New demands for passing the bill include that government offers states and territories an additional incentive of $1 billion a year in return for imposing a two-year freeze on rent increases, ongoing rent caps and improved renters' rights.
Previously the party was demanding a $1.6 billion incentive fund for states and territories to ease rental stress.
Secondly, to pass the legislation, the Greens are asking the government to commit $2.5 billion every year to purchase expiring social housing, off-the-plan homes or otherwise vacant unused properties to add to existing stock.
The sum is half of what the Greens had originally proposed.
Greens housing and homelessness spokesman Max Chandler-Mather said his party was willing to negotiate but was adamant government should not leave renters behind.
"If Labor can spend over $30 billion a year on Stage 3 tax cuts for the wealthy, they can find $3.5 billion a year to fund a rent freeze and more public and affordable housing," Mr Chandler-Mather said.
"With wall-to-wall Labor governments all across the mainland, there's no reason why national cabinet can't agree to freeze rent increases immediately and stop the rental crisis in its tracks."