Family violence focus Lay's legacy: union

Putting family violence on the front page will probably be Victorian police chief Ken Lay's best legacy, Victoria's police union says.

Police Association state secretary Ron Iddles said Mr Lay's retirement was a sad day in the force's history.

But his strong advocacy in the area of family violence would live on, Detective Sen-Sgt Ron Iddles said.

"There's no doubt putting family violence on the front page will live on and that will probably be his best legacy," he told reporters.

"Because of his attitude, we now have a royal commission which will look at family violence."

Mr Lay announced he would stand down on Monday, three years into his five-year post to care for his sick wife, Chris.

"Knowing him, and knowing his wife, it would have been a difficult decision, but I know it's the right decision and I know he's comfortable with his decision," a teary Detective Sen-Sgt Iddles told reporters.

"It shows the character of the man - he's put his family first. Sadly, some police officers don't do that."

Detective Sen-Sgt Iddles said Mr Lay managed to take the focus off internal problems within a force and shift it onto core policing issues.

"He came in at a time when force was in turmoil and had lost confidence of public and its members," he said.

"History will show he was the right man for a modern police force."

He said Mr Lay was able to re-build public trust and relationships.

As for his replacement, Detective Sen-Sgt Iddles said he would like to see a Victorian in the role.

"Victoria Police has a lot of talent in the ranks of deputy commissioner and assistant commissioner," he said.

"History would show and the public would say that previously when we've had outsiders, it hasn't worked as well."