Melbourne is moving ahead with plans for permanent anti-terror bollards, with the Police Minister also revealing an emergency siren will be installed “very soon” in the CBD.

The siren is one of a number of safety measures being introduced in an effort to improve community safety in the CBD in the event of a terrorist attack or other serious incident.

Lisa Neville told Neil Mitchell that Victorian authorities had been in contact with New York police following the lone wolf attack overnight.

“We’ve got temporary bollards the areas that police have identified as the highest risk areas – I think there are about 10 or 11,” she said.

“We are in the process of finalising the design of the permanent ones for Bourke Street they should be in place by Christmas.

“We are also upgrading all of the CCTV cameras which is what is fed into the monitoring and assessment.

“All of that work is well underway. The siren as well, you’ll recall as well we are putting in a loudspeaker in.

“We will probably do a practice run, like Sydney did.”

Ms Neville said authorities may not be able to eliminate the possibility of an attack but it was important to minimise risk.

Foreign Minister Julie Bishop has warned there could be as many as 40 jihadis who have returned from Iraq and Syria to Australia and remain a serious threat.

Ms Neville said it was of great concern, but police and intelligence agencies continued to monitor persons of interest in Victoria.

“My memory in Victoria there is around 300 persons of interest that are regularly monitored,” she said.

Click PLAY below to hear the full interview on 3AW Mornings