The former Olympic swimmer was arrested yesterday after witnesses say he was was "going off" and stabbing a knife into a chopping block.
He was later released without charge.
Australian Olympic Committee president John Coates released a statement regarding Hackett's recent behaviour.
"We are concerned for Grant's welfare," he said.
"Grant is a great Olympic champion, one of the greatest swimmers of all time, and his contribution to the Olympic Movement and to sport in general should not be forgotten.
"He inspired many young Australian children to get involved in swimming. We hope he can overcome his current challenges and we have offered him any support he needs."