Inmates at Warkworth Institution have been under a lockdown most of the day.
The measure was put in place at the medium-security federal prison, at 10:10 a.m., so staff could conduct a routine search for contraband .
Assistant Warden Scott MacPherson says the search is necessary to protect the institution as a whole, as well as its staff and inmates and that normal operations will resume when the search is over.
MacPherson also says visits have been suspended until the search is completed.