Dunbavin joins the Spireites on a month-long deal to provide cover for Tommy Lee while Aaron Chapman will go out on loan when he recovers from injury.
"I know Ian and he's very much a larger than life character who energises the place. We've lacked senior cover on the bench and if Tommy Lee was to get injured during a game, putting a young lad on with no experience is not good," said Chesterfield boss Paul Cook, who worked with Dunbavin when he was manager at Accrington.
"We've now got Ian in to provide cover while Aaron Chapman gets over his injury. The plan is to then get Aaron out on loan. Aaron is coming on leaps and bounds and he now needs to play senior football."
Dunbavin, who was with Liverpool as a youngster, has made over 150 appearances for Stanley since joining them in 2006. He was previously with Shrewsbury, Halifax and Scarborough.