Ministers have proposed that care leavers and other destitute 16 and 17-year-olds should be designated as officially 'homeless' and therefore automatically be entitled to state support for the first time.
The move follows a recommendation from Downing Street's social exclusion unit, which identified a flaw in existing arrangements during its inquiry into homelessness two years ago.
It is estimated that up to a third of the 2,000 people sleeping rough in England had been in local authority care as children, and therefore lacked family support.
The DETR said the guidelines would also effectively apply to older poeple leaving residential care. In addition, it disclosed it would recommend closer co-operation between agencies involved in housing and homelessness issues to ensure that vulnerable people received help as quickly as possible.