Accelerating power costs, high rents and dramatically rising living expenses are being blamed.

Despite Australia's resources boom, a large number of unidentified "hidden homeless" are now living on the street, or in cars, with many unable to pay for the basic necessities including food.

Executive officer for the Maitland-Newcastle St Vincent de Paul Diocese, Denise Lucas, said more working people were now seeking welfare assistance.

She said there had been a marked increase in householders seeking help to pay power bills.

Volunteers at a local St Vincent de Paul branch had been "astounded" by the number of homeless people having to sleep in their cars because they couldn't afford accommodation rentals, Ms Lucas said.

Cooranbong Community Service Centre president John Maxwell said when he first started working voluntarily at the centre four years ago the demand for relief was not particularly high.

"But now there's a steady stream of people asking for help with the basics - food and power bills," Mr Maxwell said.

The real number of homeless is almost impossible to quantify.

The Salvation Army officer for the Rathmines-to-Wyee district, Captain Tim Gittins, said he believed many homeless were staying with friends or family, rather than sleeping on the street.

"There seems to be a lot of couch surfing going on," he said.

Many people seeking help were too embarrassed to say they were homeless as well as needing food.

A Wesley mission spokesperson said there had been a major growth in demand for community, homeless and emergency relief services in the region.

"Many families are turning to credit to pay for expenses like food, telephone and electricity costs," said the CEO of the Wesley Mission, Rev Dr Keith Garner.

"Households are technically insolvent and their survival is dependent on credit which is essentially an unsecured loan," he said.

"This leads to a downward spiral of debt, stress, and too often family breakdown."