The club have also been quick in naming his replacement by handing Martin Allen a third spell in charge at Underhill.
Sanchez has expressed his "extreme disappointment" at Barnet's decision, accusing the board of showing a "lack of loyalty" towards him.
"I'd like to express my extreme disappointment at the lack of loyalty shown in me by the club," Sanchez said in a statement. "It is the same lack of loyalty the club accused Martin Allen of showing when he walked out on Barnet towards the end of last season."
Sanchez took charge of the Bees in May 2011, while Allen's previous spells in charge came in 2003 and 2011.