Striking probation officers say government plans to partially privatise the service will put the public at risk.
The probation office in Jupiter Drive, Chester, was closed to clients across West Cheshire for 24 hours from midday on Tuesday as part of action affecting England and Wales.
Members of Napo say their work in managing offenders is being undermined, resulting in a greater risk to the public.
The two companies likely to bid for the service are Serco and G4S despite the fact the Serious Fraud Office (SFO) has opened an investigation into the government's contracts with the two firms.
An audit suggested the firms had been charging for tagging criminals who were either dead, in jail or never tagged in the first place.
One of the strikers, probation officer Caroline Ballard-East said: “The government want to split probation 70/30 with 70% of the work hived off to the private and third sector.
“This is being allowed despite all the issues over tagging and public safety. It means a loss of skills, a loss of identity for probation staff and the massive issue is the public won’t be protected by the new measures.
“Our job is two-fold – risk management and public protection – alongside rehabilitation, to help people with whatever needs they have such as focusing on their thinking skills related to offending behaviour.
“This move is about money-making and shareholders rather than individuals and our society. We manage risk every day and splitting up the organisation means those risks may not be effectively managed if people get lost in the system. Once assessed at court the risk will never be managed through the process and reoffending will go up and there will be a greater risk of harm to people.”
