MORE than 30,000 Victorians are now officially homeless - more than at any time since the Great Depression.

Census figures from 2006 to be released next month will show about 3000 children are among those without permanent housing.

And welfare agencies say the figure has soared even higher during the past 12 months because of the mortgage crisis and a related squeeze on private rental homes.

Melbourne City Council is about to launch a head count of people sleeping rough in the city centre, and the Federal Government will release a green paper in May that is expected to outline a 10-year plan to combat rising homelessness.

"The numbers are dramatically up, everyone is waiting with bated breath for the official census figures to be released," Caroline Adler, manager of the PILCH (Public Interest Law Clearing House) Homeless Persons Legal Centre, said.

"But it's clear we are facing a crisis, with the need for crisis accommodation far outweighing the capacity of agencies to take clients on," she said.

Wesley Outreach Mission says it has seen a 25 per cent rise in people seeking help across the city during the past year.

"Many of these are not people with mental illness or other problems. They are families who have lost their homes," outreach service co-ordinator Annabel Austin said.

"We are seeing increasing numbers of clients seeking assistance as a result of the mortgage crisis," she said.

"We can't help people to pay their mortgages, but we are helping more and more people with basic utility bills and in buying food to put on the table.

"We have two programs -- in Footscray and Ringwood -- and it's the same story on both sides of the city. There's not enough affordable housing or well-run rooming houses for singles or people with complex needs."

Melbourne City Mission youth services manager Sherrie Bruinhout said the agency was receiving 200 requests a week for help from young people.

"But there are just four to six vacancies. We help 4000 people each week. About 14 per cent are homeless and another 30 per cent fear they will be soon," she said.

"With interest rate rises, we have seen levels of affordable private rentals drop."

Ms Bruinhout said the agency's Footscray service was helping 1000 children every week.

Victorian Council of Social Service spokesman David Imber said the effect of homelessness on individuals and families was immense: "We should all be seeking to combat this."