Victor Adebowale, chief executive of Centrepoint, said: "This is a wonderful opportunity, but we are very clear that young people at risk must not be let down by the scheme."
Centrepoint's main criticism of Gordon Brown's plans is that six months is not long enough for many unemployed young people to develop the skills and experience they need.
The Chancellor has said at least pounds 3bn raised from the windfall tax will be used to offer the young unemployed a choice of a six-month job subsidy, a training scheme, voluntary work or a job on an environment task force. But Mr Adebowale said: "This will not be long enough for some young people."
William Craig - who lives at Centrepoint's Camberwell Foyer, a residential scheme highly praised by the Chancellor, said: "What qualification can you get in six months? I want a brighter future for myself. I want to educate myself to the extent of a degree." Mr Craig will start a two-year part-time access course in September.
Mr Adebowale said that one in seven of the young people who come to Centrepoint have difficulty with reading, writing and sums. He also stressed the need for the Government to end the rapid withdrawal of benefits, especially housing benefit, from people who do find work.
"The benefit system must be changed in order to run in partnership with welfare to work," he said. He also criticised the Government's intention to threaten young people who do not join one of the four planned schemes with loss of benefit.
"To start talking about sanctions before you've worked out what the incentives are is the wrong approach for young people," he said.
Centrepoint has been invited to make a private submission of recommendations to the Chancellor, and will be sending him a detailed set of proposals.
Mr Adebowale stressed that the new schemes must look very different from old ones like the Youth Training Scheme if they were to have any credibility with young people.
Centrepoint said with one in 20 young people - that is, more than 380,000 - facing the risk of homelessness in any year, welfare-to-work would have to be integrated with housing support.
The Government's new schemes ought to be run as partnerships between the Employment Service and the private and voluntary sector.
Individuals' progress would also have to be monitored during and after their six-month placement, Centrepoint said. Otherwise the scheme would turn into a short-lived fix rather than helping unemployed young people in their long- term development.Reuse content