The government is expected to come up well short on its commitment to provide 3000 extra income-related rent subsidies.
And the Labour Party says it is another blow to vulnerable New Zealanders who can not afford homes.
Income-related rent subsidies make social housing affordable and available to those on low incomes.
Prime Minister John Key said last year the government would increase the number of rent subsidies from 62,000 to 65,000 by 2017/18.
But Labour's housing spokesperson Phil Twyford said official new figures, provided by the government, showed it would fail to deliver the 3000 extra subsidies it promised by 2017/18.
"The government has fallen well short of their target, instead of delivering 3000 new subsidies, they've fallen short by more than 1300 - so they've really only delivered a little over half of what they promised they would," Mr Twyford said.
Mr Twyford said the growing number people sleeping in their cars was a direct result of the government's policies.
"What we see is a government that is far keener on selling off state houses, they've sold off over 2500 state houses since 2011 and they're moving down the track of selling a whole lot more state houses, but they're not so good at actually increasing the number of people who can actually get a state house," Mr Twyford said.
"If we had more state housing we wouldn't have this problem with homelessness."