Australian authorities are being urged to consider a new "duty to assist" law that would force governments to help homeless people find accommodation, amid warnings homelessness is spiralling out of control and funding is drying up.

Key points: The law would require the government to follow a three-stage process

The law would require the government to follow a three-stage process It has been implemented overseas and helped 80 per cent of "priority" homeless people find accommodation

It has been implemented overseas and helped 80 per cent of "priority" homeless people find accommodation New analysis shows Australian government funding for homelessness is dropping in real terms

In 2015, politicians in Wales became the first to legislate a requirement for governments to act, and the idea is now being trialled in Canada.

Peter Mackie is a global expert in homelessness who is visiting from Wales to champion the idea and talk to experts in Australia.

He said in most Western countries authorities did not act until the situation became critical, and this needed to change.

"We wait until crisis, wait until people are on the streets or are literally homeless," he told the ABC.

In Wales, the law outlines a three-stage process that local governments are required to follow.

STEP 1: Help to prevent. Local authorities must take action and offer resources to help people at risk of homelessness

Local authorities must take action and offer resources to help people at risk of homelessness STEP 2: Help to secure. If step one has failed, local authorities must take action to help secure accommodation. They are not required to provide accommodation. Rather, they have 56 days to take steps to help

If step one has failed, local authorities must take action to help secure accommodation. They are not required to provide accommodation. Rather, they have 56 days to take steps to help STEP 3: Duty to secure. If steps one and two fail, step three places an absolute duty on local authorities to secure accommodation for people if they are deemed to be in priority need and are unintentionally homeless

At each stage there are certain rights outlined for the person seeking help, but also requirements put on them, such as having to comply with local authority guidelines.

After the first year in effect, the data showed 65 per cent of people who presented at stage one successfully avoided homelessness.

Of those who went all the way through to stage three, 80 per cent of those deemed to be priority cases were successfully housed.

Social housing is a key plank of the "duty to assist" law. ( ABC News: Margaret Burin )

"Everybody who comes to the door has a right to meaningful help," Dr Mackie said.

"And it sounds like people should be doing that, and local authorities, national governments should be doing that, but it's just not what happens across the globe."

Dr Mackie said before the law was introduced in Wales, homeless people were repeatedly told there was no housing available.

"What we saw when we brought in the legislation is local authorities going and finding private rented housing that we didn't know existed to be rented out," he said.

Federal funding 'drying up'

The plan has been met with qualified support by Australian homelessness advocates, who say more early intervention is needed but point to funding differences that make it hard to implement here.

It is estimated that on any given night 116,000 Australians are homeless, and the number has been rising over the past five years.

There are calls for a national homelessness plan. ( ABC News: Danielle Bonica )

"I think that it's really worth having a look at," Council to Homeless Persons chief executive officer Jenny Smith said of the law.

"It would position us further up the cliff. We wouldn't be always intervening at the bottom of the cliff."

In Wales, about 17 per cent of accommodation is social housing. In Australia it is about 5 per cent nationally, and as low as 3 per cent in some areas, according to the Council to Homeless Persons.

"It was the global financial crisis that saw the last significant investment in social housing, and we haven't had that since," Ms Smith said.

"So we would need to see that investment in the homelessness services."

New analysis released this week by Homelessness Australia found federal government investment in social housing and homelessness had been falling in real terms.

It found spending had not kept up with population growth and inflation since 2014-15 and services were $82 million worse off this year as a result.

Last month the new assistant minister responsible for reducing homelessness, Luke Howarth, told the ABC he wanted to put a "positive spin" on the issue, and the Morrison Government was focused on tackling it.

"I want to put a positive spin on it as well and not just say Australia is in a housing crisis when it affects a very, very small percentage of the population," he said.

Ms Smith said the last national strategy to tackle homelessness was back in 2008 and she called for a new plan that included every level of government.

"We are calling on the Federal Government to invest more in social housing and to lead a process that engages all three levels of government — federal, state and local — in order to establish national and state-based homelessness plans with which to make some progress," she said.