A senior Corrective Services bureaucrat sent an aggressive, intimidating letter to a prisoner support group after it gave evidence critical of the jail, including allegations that an intellectually disabled detainee was mistreated.

The senior public servant has since been rebuked by Justice Minister Shane Rattenbury, who is angry that his government could be seen to be attempting to silence critics.

Justice Minister Shane Rattenbury has rebuked his directorate after it sent a threatening letter to a prisoner support group, which gave critical evidence to an inquiry. Credit:Rohan Thomson

Prisoners Aid, a small organisation reliant on government funding, gave evidence last month to an inquiry into an auditor-general's report on the rehabilitation of inmates at the Alexander Maconochie Centre.

The group raised a number of issues of concern, including one incident detailed by the group's vice-president Shobha Varkey, who alleged an intellectually disabled woman with epilepsy and a brain injury was improperly restrained and pushed by guards.