The Daily Telegraph reports that the Bulldogs are expected to cut current interim coach Steve Georgallis in what will be the biggest move.
Other club legends expected to get the axe is head of high performance Tony Ayoub and strength and conditioning coaches in Harry Harris and Tony Grimaldi.
As they were all off-contract, Barrett has been forced to either extend them or move the club in another direction.
He will now bring his own coaching staff to Belmore next season.
Canterbury insiders insist change is needed for the club to get off the bottom of the NRL table.
Dan Ferris, Gold Coast head of high performance, is expected to join Barrett at Belmore, who worked together at Manly.
Georgallis was an assistant coach at the club before taking on senior coach role when Dean Pay was sacking in July.
Steven Antonelli was another assistant coach who quit a month before Pay was sacked.
Those close to the club believe Barrett and his new coaching staff will bring in a more flamboyant playing style next season.
— Canterbury-Bankstown Bulldogs (@NRL_Bulldogs) August 7, 2020