Senior probation officers have attacked plans to offer private companies and charities payment-by-results for supervising people released from jail.
Supervisors would be paid according to how well they prevented reoffending in inmates' first year after release.
But the Probation Chiefs Association said the payment-by-results plan was "untried and untested".
Defending the plan, Justice Secretary Chris Grayling said it was "all about reducing crime".
Mr Grayling told the BBC: "The truth is that reoffending is currently rising.
"Six hundred thousand crimes a year are committed by people who are going round and round the system."
He confirmed that, under the proposals, every offender leaving jail - including those who have spent just a few days in prison - will have to complete a year-long period of supervision that will see them returned to custody if they reoffend.
Currently, offenders who have a sentence of less than 12 months are not supervised on release.
But figures from the Ministry of Justice show that while 46.9 % of all adult prisoners commit a further offence within a year of release, the reoffending rate is significantly higher - 58.2% - for those sentenced to less than a year.
Mr Grayling said: "The biggest block of those that reoffend are those that are in prison for less than a year... they leave with only £46 in their pocket and that's it."
The current system supports some 250,000 ex-offenders a year, he said, while the new plan would bring another 50,000 or so people jailed for up to 12 months into the net.
But the government is not providing any extra funding; the supervision, under a system of 21 contracts, will be the responsibility of voluntary groups, charities and private companies, who will be paid in full only if a certain proportion of offenders don't commit further crimes.
Contracts will be awarded on the basis of "best value and innovation" in tackling reoffending.
Mr Grayling said: "We have a system at the moment where only around 25% of probation time is spent working with offenders.
"There has got to be room for efficiency in the system - and for the big section that aren't getting support," he added.
He will set out his plans in the House of Commons as MPs continue debating the government's legislative programme as set out in the Queen's Speech.
Under Mr Grayling's plans all prisoners will receive support for a minimum of 12 months to help them find accommodation, get a job or training and tackle any alcohol or drug problems they may have.
Long term offenders will continue to be monitored by the probation service for about the same length of time as their prison sentence - for example, an offender given an 18 month sentence will serve nine months in prison, and nine months on licence in the community.
Mr Grayling said he was not "setting the rules" on levels of supervision - some offenders will be monitored intensively, others less so. But the prison estate will be reorganised so that most offenders are released into the area where they will be supervised.
The Probation Chiefs Association said the system was "untried and untested".
Sarah Billiald, of the Probation Chiefs Association, told the BBC: "Our message is to ask really, why, when you have such a high performing service... it has met all its targets... why would you not build on that success rather than dismantling it later?"
Ian Lawrence, acting general secretary of probation service union Napo, said: "Part of the rationale of government in sacrificing the Probation Service is because the reoffending rates of prisoners serving 12 months or less is high and climbing.
"However, except for a very small number of young offenders over an inadequate three-month period, the Probation Service has no statutory responsibility for supervising that group; nobody does. This decision is purely ideological and is based on cutting costs, which will certainly compromise public protection."
Red tape fear
Andrew Neilson, of the Howard League for Penal Reform, argued that the plans represented "an admission of the abject failure of short-term prison sentences" and that the government should make greater use of community sentences.
He said: "These plans set people up to fail. Rather than scrapping short prison terms, the government is creating disproportionate sentences for minor crimes, so that a two-week prison sentence becomes a year and two weeks of being trapped in the criminal justice system."
But the Rehabilitation of Addicted Prisoners Trust (Rapt), which provides drug treatment services for offenders, welcomed the idea of enhanced monitoring and support.
Mike Trace, Rapt's chief executive, said it would be possible to achieve greater supervision without significantly more resources - as long as the process did not get caught up in red tape.
Colin Lambert, a former prisoner and now project manager at the offender charity St Giles Trust, told the BBC it was a "great idea".
"I know that they are saying payment-by-results is untested, but what we have now doesn't work so we need new ideas," he said.