The Green Party is accusing the Government of breaking its promise to insulate every state house by the end of 2013.
In answer to written questions this week, Housing Minister Nick Smith said of the 30 percent of the 68,000 houses under Housing New Zealand's management had not been insulated.
Greens Party co-leader Metiria Turei said National promised in its 2011 election manifesto all state houses which could be practically insulated would be.
"National has failed to do so and in the meantime, the families who live in those homes are living in cold, damp homes that make their kids sick.
"It's not acceptable for National to break its promise."
If elected to Government in September, the Green Party would restart home insulation scheme Warm Up New Zealand to insulate a further 200,000 homes, Ms Turei said.