Victoria Police on Sunday warned Andrew Darling has been known to be violent and go "off grid" in bushland for days at a time.
The 52-year-old was in post-sentence custody at the Corella Place facility on Warrack Rd at Ararat when he fled on Sunday, prompting officers to search for him.
"Corrections Victoria can confirm that a 52-year-old offender absconded from the Corella Place residential facility around 2am on Sunday," a spokesmann for the Department of Justice and Community Safety told AAP.
"Victoria Police was notified immediately and Corrections Victoria is assisting with investigations."
Darling, who is a registered sex offender, is described as about 175cm tall, with a strong build and tattoos on his arms, legs and back.
He has short grey hair and a long red-and-grey beard, but could have shaved since his escape, police said.
Officers urged members of the public not to approach Darling if they saw him, and instead call triple zero.
He has strong connections to Ballarat.
The Corella Place residential facility is where serious offenders who have completed their sentences undergo further court ordered treatment and supervision, including electronic monitoring.