Foreign property investors will be slugged with higher fees and taxes under proposed changes by the NSW government that will raise billions of dollars to help first homebuyers.

The Foreign Investor Surcharge Duty will be doubled from four per cent to eight per cent from July 1, while the annual land tax surcharge on foreign buyers will rise from 0.75 per cent to two per cent a year, News Corp Australia reports.

The measures are expected to raise $2 billion over the next four years.

Meanwhile, first-home buyers who are buying existing properties worth up to $650,000 will be exempt from paying stamp duty, the ABC reports.

At present, the exemption is only available for those purchasing new properties.

There will also be a range of changes to first-home buyer grants.

The package will be taken to cabinet on Thursday with an announcement from Premier Gladys Berejiklian, Treasurer Dominic Perrottet and Planning Minister Anthony Roberts expected later on Thursday.

Ms Berejiklian vowed to make housing affordability one of her key priorities when she became premier in January.

NSW shadow treasurer Ryan Park on Thursday described the rumoured $2 billion housing affordability package as a reworked Labor policy that was too little, too late.

“They’ve missed the boat,” he said.

“They sat on their hands, there was nothing in last year’s budget and, a year on, we’re in crisis.”

Mr Park said the proposal to raise the Foreign Investor Surcharge Duty from four per cent to eight per cent was lifted from an ALP proposal.

“(Therefore) I have no problems with that,” he said. “We made it first.”

The opposition claimed Thursday’s announcement was timed to deflect attention from Ms Berejiklian’s backflip on the emergency services levy earlier this week.