Offenders given community sentences went on to commit 50 violent or sexual attacks a day, figures have showed.
These included more than 170 child sex offences, 500 sex offences and 550 serious violent attacks in 2009 alone, Ministry of Justice (MoJ) figures showed.
It comes as separate figures showed up to 20,000 offenders given cautions are going on to commit another offence within a month. And one in four offenders given community sentences or released from prison early on licence fail to comply with the terms set down by the authorities.
The prison population in England and Wales is at record levels with more than 87,000 behind bars and community sentences, along with other alternatives to custody, are a key element of Justice Secretary Kenneth Clarke's "rehabilitation revolution".
Officials said reoffending rates were falling, but added that they were still too high and the Government was "determined to break the cycle and address the root causes of this behaviour".
In a written answer to Priti Patel, the Tory MP for Witham in Essex, Justice Minister Crispin Blunt said a total of 18,133 violent or sexual offences were committed by offenders within a year of them starting a community sentence in 2009, the latest year for which details are available. These included 172 child sex offences, 518 sexual offences, and 564 serious violence offences, the figures showed. A further 16,879 so-called non-serious violence offences were also committed.
Other figures showed that 14,994 offences were committed by adults within a month of them being cautioned in 2009. And a further 6,007 offences were committed by children and teenagers under 18 within a month of being given a reprimand or final warning. The figures rose steeply, going up to a total of more than 30,000 offences by adults within two months, and more than 70,000 within six months. After a year, 85,750 re-offences were committed by adults and 39,697 by under 18s.
The figures, which do not reflect actual numbers of offenders but the number of re-offences committed, showed that adults who received an out-of-court disposal in 2009 and reoffended, committed an average of 2.3 further offences each over 12 months.
A Ministry of Justice spokeswoman said: "Reoffending is falling and the overwhelming majority of people sentenced to community orders, or handed out-of-court disposals, do not commit further offences. If they do, they face a potential prison sentence.
"Despite this, we believe that levels of reoffending in this country are too high, which is why we're determined to break the cycle and address the root causes of this behaviour. We want prisons to be places of hard work, community sentences to be demanding and unpaid work to benefit local communities. We are currently reviewing community sentences to make them tougher, and will set out our approach in due course."