The Greens' housing policy is being called 'nonsensical naivety'.
The party says it could wipe the 18,000-strong social housing list clean within five years by building more rentals, and offering Crown guarantees for community providers.
OneRoof commentator Ashley Church says it shows the party doesn't know how the sector works.
He says there's about 550,000 rental properties, of which about 440,000 are owned by the private sector.
"So to assume that they are going to fix the need for rental housing through a relatively small part of the market is naivety to the extreme."
Church says it would more effective if there was help for private landlords to improve the supply and quality of rentals.
"That's what's going to stop this problem over time, not beating up on them while at the same time making silly claims they can't actually deliver on."
There is some support for the policy.
Auckland City Missioner Chris Farrelly says it would be a good way to unite government social housing with the multitude of community programmes.
"Community housing provider have access to land through different mechanism, they just need assistance to actually put the housing on the land."