A network of loudspeakers to be installed across Melbourne's CBD to warn people during terrorist attacks or emergencies is almost three quarters complete.
Sixty-five speaker sets have been installed at sites including Federation Square, Flinders St Station and the Bourke Street mall, with more than 90 sites to be completed by the end of 2018.
"The new speaker system, as well as permanent bollards and CCTV, will provide even greater protection and warning for the community in the event of a serious incident," Police Minister Lisa Neville announced on Monday.
Victoria Police will decide when the speakers are used and what message is broadcast.
Ms Neville says the messages might require those in the CBD to "move to a particular area, leave a particular area, or move to or stay inside the nearest building".
