Rainer and the Social Market Foundation are today presenting Home Secretary John Reid with a collection of essays looking at the role the third sector could play in probation.
Probation is one of the most controversial areas in the Government's public services agenda, and the essays highlight the positive impacts voluntary bodies could have on the National Offender Management Service.
Noms was set up in 2004 to introduce market competition to detention and probation services, but a Noms Bill is yet to be published.
Joyce Moseley, chief executive of Rainer, wrote her essay to help ease the fears about charities delivering probation services.
The essays are also intended to spark debate about the ethical issues that could arise from charities getting more involved in the criminal justice system.
"We need to be realistic that, in certain areas, a greater role in public service delivery could pose a serious challenge to public trust in the sector," wrote Stuart Etherington, chief executive of the NCVO, another contributor.