Workers in the criminal and family courts across England and Wales said cuts and court closures have put significant pressure on the service which is leading to mistakes being made.
Staff in one region, Durham Tees Valley, told a survey by Napo, the union for probation and court staff, that constraints had led to offenders getting off lightly.
"Possibly because of shortcuts, unpaid work requirements have been imposed where alternative, more robust sentencing was needed," said the union's report.
"Staff ... report a number of cases where curfew orders have been imposed in cases of domestic violence which significantly increases the risk of harm to victims."
Officials even reported cases in which the courts had imposed offending behaviour programmes on offenders as punishments - such as drink and drug courses - even though the programmes had been closed down.