There are about 8500 people living in motels and other temporary accommodation, some in conditions one of the Government's own ministers has described as "inhumane".
Many tenants have complex mental health and addiction issues, and intimidation is rife in some places.
Ardern said the Government already provided wraparound services to some in emergency accommodation, and it was considering boosting this.
Bernie Smith of Monte Cecilia Housing Trust. Photo / RNZ
Monte Cecilia Housing Trust chief executive Bernie Smith said it was ridiculous not everyone could access the services.
"It's certainly a moral failure because we know if the Government had the fortitude to make the change, they would.
"It needs the Government to commit to every family and every motel across the country having social work support."
Social Development Minister Carmel Sepuloni said support was provided according to need.
"We need to continually monitor whether or not we are getting to enough families and providing families with the support they need.
"Some move into emergency accommodation and out relatively quickly, but there certainly are a number who do need wraparound support."
Smith said people should not be forced to ask for help.
He said the Government had four years to come up with a plan and he wanted action now.
"We're actually creating a generation of homeless children who are not only homeless and in poverty but, sadly, are going to be in our mental health and penal institutions because we haven't looked after them today.
"And it's not good enough in New Zealand."
Smith said once families left emergency housing for transitional housing they got a good level of wraparound care. He said the service should be expanded to include everyone right from first entering emergency accommodation.
Salvation Army national practice manager Jono Bell said work needed to be done to find out how many people were missing out on help they needed.
"Some people are getting the support but others aren't.
"Our question would be, what is that ratio? What are the numbers that aren't getting that support? And how do we ensure that we could ramp-up services to ensure that we'll be able to provide that wraparound support."
The PSA union represents social services workers and its spokesperson Alastair Reith said social workers were already under the pump and the Government would need to front cash to get wider support to those in emergency accommodation.
"If you talk to pretty much any social worker in New Zealand, they'll say they have a lot to do and not enough time to do it.
"So it's definitely possible, but ... this workforce [is] already stretched [and] they'll need more resources and more funding to do it."
