The electronic tagging scheme is being extended to allow prisoners to be released earlier to ease prison overcrowding, according to probation officers.
Only prisoners serving less than four years are eligible for tagging
The National Association of Probation Officers (Napo) said governors were being told to free more prisoners - even those considered likely to reoffend.
An extra 1,000 prisoners would be freed every month - raising the monthly average to about 2,600, says Napo.
It said it was "a panic measure" as prison numbers have risen to 75,000.
The union's magazine, Napo News, said the only prisoners eligible for release under the home detention curfew scheme who would remain behind bars were those posing "a risk of harm to the public".
The number sent back to prison for breaching their curfew could jump from 288 in
October to 500 or 600 by the summer.
Only prisoners sentenced to less than four years' imprisonment were eligible for tagging.
In addition, many offenders are not allowed early release, including those
convicted of sex, child cruelty and racially-aggravated crimes.
Napo assistant general secretary Harry Fletcher has called for increased investment in the probation service "to create more capacity for less
serious offenders to be supervised in the community".
A Prison Service spokesman said: "There has certainly not been any central instruction to change the way
individual governors implement home detention curfew."