Children's Commissioner Dr Russell Wills has described the Residential Tenancies Amendment Bill as a wasted opportunity which will not improve the often-appalling conditions in which children live.
The new bill being heard by a parliamentary committee was originally intended to improve the poor quality of rental housing, but has failed to achieve that.
Dr Wills, whose five-year term ends in the middle of the year, will present a submission to the select committee tomorrow.
He told Checkpoint with John Campbell the bill would not deliver the warm, dry, housing children needed.
"The families that we see on children's wards with respiratory infections often live in appalling housing: cold, damp and mouldy. Sometimes it's not fit for human habitation."
The evidence was clear, that only children who live in sub-standard housing got these respiratory infections, he said.
A May 2013 promise by the government to look at a warrant of fitness for housing had been broken.
The bill lacked a standard for insulation, a heating and ventilation standard and an enforcement regime, he said.
"We need to have an enforcement regime. The people we're seeing on children's wards never complain to the Tenancy Tribunal. They don't and they won't."
The home was the single biggest influence on a child's health, and was the least regulated aspect of the environment, Dr Wills said.
"We should be able to guarantee for all children in our country that they will live in a warm, dry, healthy house. This bill doesn't do that and I think it should."
Dr Wills said he would be making these points to the select committee tomorrow.