A housing report by the Salvation Army has found a third of New Zealanders are struggling to access good quality, secure and affordable housing.
The report says young people and non-homeowners who are retiring are the most likely to need help.
Report author Mr Johnson says the proportion of people struggling to get good affordable housing has been at about 30% for a number of years, but of late those people seem to be getting more and more desperate.
He told Radio New Zealand's Nine to Noon programme the Salvation Army's office in South Auckland is constantly dealing with families in need of accommodation and some turn up with nowhere to sleep that night.
"It seems as though the depth of the problem and the desperation of the problem is getting worse," he said.
"In some respects ... it's to do with the transitions that Housing New Zealand are going through and the extent to which Housing New Zealand is able to respond (those) sort of acute housing needs."
Mr Johnson says Housing New Zealand has not been housing enough families and it has made it harder for them to get on the waiting list.
However Housing Minister Nick Smith says a large number of families have been housed recently.
"In the last month we've had some of the highest levels of placement of families in our state housing."
Dr Smith said a change in criteria has to give priority to families with risk of rheumatic fever.
He acknowledges there is a gap in the housing market for low-income elderly people and he wants to have further discussions with the Salvation Army about this.
Mr Johnson, the Salvation Army's policy advisor, says Government policy shifts in 1993 to dismantle home ownership assistance policies and introduce the accommodation supplement were not evidence-based.
He says consecutive governments have failed to gauge the impact of that and have not used common sense or compassion to drive housing policy. Mr Johnson says a wide-ranging and fundamental review of the policy is urgently required.
Listen to Alan Johnson on Nine to Noon