The comments came after the PBNI said it was informed of an increase in the risk of attack they face from dissident republicans. The organisation said the risk may be higher for employees living and working in republican areas.
Former Justice Minister Mr Ford said probation staff provided an essential service to the people of Northern Ireland.
“They are responsible for the supervision of offenders, but they do so as social workers, helping individuals with housing, employment and education by building positive relationships. They also do so with offenders from every kind of background.
“Their work is valued by many voluntary and community groups with whom they partner. Probation in Northern Ireland is among the most successful services in these islands.
“I utterly condemn those who are now threatening this group of public servants and call on them to immediately lift the threat, and allow probation staff to work freely without hindrance.”