The Bulldogs ended months of speculation when chairman Ray Dib informed Hasler of the club's decision.
The veteran coach has paid the price for failing to take Canterbury to the finals for the first time since his arrival in 2012.
Des Hasler Photo: PHOTOSPORT
It comes just months after the Bulldogs had announced a two-year contract extension for the dual-premiership winning coach.
But the club claimed that was never binding, allowing the board to step in and prevent Hasler staying on into the 2018 season.
"Today, I informed Des Hasler and his management of our decision to pursue a new head coach for our club, effective immediately," chairman Ray Dib said on Tuesday in a statement.
"These types of conversations are never easy, especially when they involve people we respect personally and professionally.
"However, the club believes the decision to change our football leadership was absolutely necessary."
It's understood Dib had completed a two-day review of the team's football department last week, which included speaking to just three senior players.
It's also believed he has kept incoming half Kieran Foran abreast of the situation, given his close links to Hasler while at Manly.
It's unclear what Hasler's departure means for former Warriors player Kieran Foran. Photo: PHOTOSPORT
It's not thought that Foran has a get-out clause in his contract if Hasler isn't at the club.
It could also open the door for sacked South Sydney coach Michael Maguire to return to the NRL through the Bulldogs, while Dean Pay, Jim Dymock and Todd Payten are considered other options.
"The club will now begin its search for a new head coach and will provide further information once that process has been completed," Dib said.
The decision could also open the door for Des Hasler to coach the NSW State of Origin team next year, having worked with the Blues as an assistant before landing the top job at Manly in 2004.
Hasler's 2017 season marked the first time he had missed the finals since his rookie year as a head coach, while he took Canterbury to grand finals in 2012 and 2014.
