The Housing Minister has lashed out at new statistics showing nearly 20 per cent of social housing was left vacant despite thousands of families desperately needing a home.

A total of 786 houses built by social housing agency, Kāinga Ora between June 2022 and October 2023 were left unoccupied by October 31 that year. Of those homes, 287 were vacant for more than four months.

This is despite, as minister Chris Bishop put it, "thousands of families waiting for social homes such as these".

Bishop said the number of new social houses sitting vacant in New Zealand was "completely unacceptable", stating he had written of his disapproval to the board of Kāinga Ora Homes and Communities.

More than 25,000 people are on the social housing waitlist, which is almost 20,000 more than when the previous Labour Government took office.

Bishop said social homes should not be left empty "for a day longer than absolutely necessary".

"It is disgraceful that New Zealanders needing a warm, dry home for their family are waiting in motel rooms, in cars and on family members’ couches while hundreds of newly built social housing units sit empty," he said.

"While I understand there may be instances where, for valid reasons, it takes time to fill a new home, the timeframes identified in this response are well beyond what I consider appropriate."

The statistics were the result of an Official Information Act request by a member of the media.

"It is critical that Kāinga Ora is focused on efficiently placing tenants into social housing across New Zealand and works with much greater urgency to do so," he said.

Bishop has historically been critical of Kāinga Ora’s financial management and had promised to review its performance within 100 days of the new Government taking office.

Former Prime Minister Bill English is to head up an independent panel that will review the housing agency, which has assets totalling $45 billion.

Bishop recently said he was particularly concerned about the way Kāinga Ora has engaged with the private sector.

"Some of the feedback I've had over the time I've had the housing portfolio is that Kāinga Ora has poor relationships with the private sector that it needs to build on, so we want to have a look at that."

Bishop said he's always had concerns about the way the agency had been operating, considering its 2022/23 financials revealed a forecast deficit of $500 million.