A group of homeless men have made a haven for themselves inside a central Auckland bridge.

Rates used to upgrade Auckland's CBD may soon be spent on the homeless, as projections show more than 26,000 people could be without a roof over their heads in the region by 2021.

While millions of dollars have been spent helping the region's homeless, a new report to Auckland Council's City Centre Advisory Board shows there is still an unmet need for homelessness support services.

The report shows homelessness could rise to 26,522 people by 2021 - almost the size of Timaru's township of 27,650 residents - based on average increases between censuses.

Census 2013 showed 20,296 people were homeless in Auckland.

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Council staff are investigating funding homelessness initiatives through the city centre targeted rate.

CHRIS MCKEEN/STUFF A homeless person sleeps with their belongings on Queen St in Auckland's CBD.

They are also looking at "temporary solutions", such as mobile showers for homeless people.

The city centre advisory board advises the council on how to spend the targeted rate, which is paid by central Auckland residents and businesses to upgrade and develop the city centre.

Currently, it does not fund homelessness support services.

However, Auckland Council arts, community and events general manager, Graham Bodman, said the targeted rate had previously contributed $2 million to the James Liston Hostel upgrade, which was the central city's only emergency housing provider.

The Liston upgrade had a total budget of $3.9m and would include increasing the hotel's capacity by five beds.

"This redevelopment is currently underway and is anticipated to be complete by mid-2019," Bodman said.

JASON DORDAY/Stuff Mayor Phil Goff and Housing First Auckland’s Fiona Hamilton have announced Auckland’s first region-wide count of people living without shelter

Auckland Council staff were now working to "identify options for homelessness support services which build on and strengthen those already provided".

"Our investigations will involve reviewing the evidence and consulting with key stakeholders to develop options for effective interventions which the Auckland City Centre Advisory Board can consider," Bodman said.

Mayor Phil Goff previously conceded the ball had been dropped on understanding and solving Auckland's ballooning homelessness problem – officials have little data on the size and nature of what he called a "chronic homelessness" issue.

PHIL WALTER/GETTY According to a Auckland Council report, homelessness in the region could stand at 26,522 by 2021.

He made the comments while announcing a $375,000 homelessness census would be carried out in September in an effort to eradicate the region's rough sleeper problem.

Auckland Council is currently providing financial support for a range of other homelessness initiatives.

That includes spending more than $1 million on the highly successful Housing First Auckland pilot.

By the start of July, 83 per cent of 443 homeless Aucklanders housed through that programme had kept a roof over their head.

Another $475,000 was being given to the Auckland City Mission redevelopment to cover costs such as consent charges.

The new City Mission – Mission HomeGround – would include 80 social housing units with services to improve tenants' wellbeing and help them stay off the streets.

Central Government was helping fund the $90m project and Auckland City Mission was fundraising for the extra $21.8m.

However, the report to the city centre advisory board stated "further investment is required to support a response to homelessness in the city centre".

It suggested providing better public amenities, such as showers and toilets, could "enhance dignity and wellbeing for the rough sleeping community".

In May, the City Centre and Waterfront Executive Steering Group asked for a strategy showing long-term plans for public amenities in the CBD. It was expecting a report back from council staff in September.

"While a policy approach is being scoped, the feasibility of temporary solutions, like mobile showers for homeless people, is being investigated."

Council staff were also investigating options to be assessed against the targeted rate funding criteria. They would report back to the advisory board in late 2018.