On making the move Bryce will join recently-appointed Rebels head coach Tony McGahan whm he reported to during his first season with Munster in 2011.
Disappointed to be leaving the province after two seasons, Bryce indicated the move was the best opportunity for his family and based his decision around same, and although contracted to the province until the summer 2014 the management supported the decision.
Munster head coach Rob Penney commented: "We are sorry to see Bryce go, he is a great guy with a fantastic work ethic and has always been excellent for us.
"Obviously the timing isn't ideal from our point of view, to lose a guy of his calibre during the season, but he leaves a strength & conditioning department that are in great shape to continue on the work, and we understand this is an opportunity for him and his family and we wish him all the best."
Cavanagh himself added: "I've really enjoyed my time with Munster Rugby and leave privileged to have experienced the unbelievable culture here.
"It is hard to walk away from such a group of dedicated players and staff, but I know returning to Australia is the best thing for me and my family at this time."