The NSW government's housing affordability plan is an "insult" to struggling first home buyers, says Opposition Leader Luke Foley.
Premier Mike Baird has announced Tuesday's state budget will inject $400 million into speeding up the delivery of more housing, which the premier says will put downward pressure on prices.
The Housing Acceleration Fund investment would help those trying to break into Sydney's hot property market, Mr Baird said on Sunday.
But the plan has been slammed by the opposition, who say the funds are a "drop in the ocean" compared to the billions collected in stamp duty.
"The ludicrous state of the Sydney property market is literally providing rivers of gold to the Baird government," Mr Foley said in a statement.
"To return a meagre six per cent of stamp duty taxes collected into housing affordability is an insult to first-home buyers across the state struggling to find a house."
Families with low and modest incomes were being left behind in the government's plan, the opposition leader said.
"Releasing more land is not the silver bullet to fixing housing affordability," Mr Foley said.
Earlier, Mr Baird said "supply, supply, supply" was the key weapon in housing affordability in the long term.
"Housing affordability requires many levers to tackle it," the premier said.
"The principal lever that the state government can do is increase supply."
First-home buyers were also supported through grants, up about 10 per cent this year, and stamp duty concessions of up to $30,000 if they bought new properties, he said.
"We're encouraging first-home buyers through everything we're doing, but the principal thing we can do ... is get supply moving," he reiterated.
When queried about abolishing stamp duty tax, Mr Baird said he was all about lower taxes, but doing it in a way that was responsible and in the state's best interest.
"We're happy to play a constructive role in tax reform ... we are happy to consider stamp duty in the long term," he said, adding that the priority right now was housing affordability.
Another way the Baird government hopes to tackle housing affordability is through an independent Greater Sydney Commission.
Funding will be allocated in Tuesday's budget for the London-style commission that will include local councils and the state government working together to ensure 664,000 new homes are built by 2031 in areas supported by the necessary infrastructure.