One of the programme's spokespeople, University of Otago public health researcher Michael Baker, said tenants in social housing were "an extremely vulnerable group".
"This is not middle New Zealand who is living in social housing ... The median age is 20, so half are under 20 years of age. Almost 40 per cent are sole parent families. They are extremely low income."
He said that when people moved from being applicants to becoming tenants, their hospitalisation rates fell by about 25 per cent.
At present, the three-yearly reviews applied only to the 10,200 people who began their tenancies under the current Government. The bill would expand the reviews to 53,200 tenants.
As a result of the law change, it was estimated that 1000 tenants would move into independent housing in 2015/16, increasing to 3000 in 2016/17.
Housing Minister Nick Smith said the people who would have to leave houses as a result of the expanded reviews was relatively small, and he was confident that none would be put at risk because of the change.
He said that there were 6000 people in state houses who were paying the full market rent, which showed they were earning enough to move into a non-subsidised home.
VisionWest Community Trust chief executive Lisa Woolley said it was too early to make all tenancies reviewable because there were not enough affordable homes for tenants to move into.
The wider Government subsidies for social housing were accompanied by greater powers - Housing New Zealand would be able to review tenancies of non-government providers and make appointments to their boards.
Some NGOs challenged these new powers, saying that the private providers usually had a much better understanding of their own tenants and the risks associated with changing their housing.
Social housing reforms
• Income-related rent subsidy extended to all social housing providers.
• Reviewable tenancies extended to all Housing New Zealand tenants and some non-government housing providers' tenants.
• Housing needs assessment moved from Housing New Zealand to Ministry of Social Development.