Melbourne, Dec 11 (IANS): Loudspeakers were being installed across Australia's Melbourne city on Monday as part of a major security upgrade to warn people of terror attacks.

The new measures are the recommendations of a counter terrorism review that occurred after a number of extremist incidents this year, reports Xinhua news agency.

In January, a vehicle attack in Melbourne resulted in the deaths of six people, while in July a deadly terror siege killed two men, including the gunman, on the outskirts of the city.

Last month, a plot to gun down innocent people in Melbourne's Federation Square was thwarted by authorities.

The $7.5 million initiative will also include extra CCTV cameras in the Central Business District and the construction of more pavement barricades to prevent cars from entering busy walkways.

"The loud speakers will allow us to put out warning messages in the event of an incident occurring whether it be a terrorist event or whether it be another mass casualty incident, or one that's of high risk," Victoria Police Acting Chief Commissioner Shane Patton told the media.

"It will allow us to inform the public in the city where they should be going, what they should be doing and making sure they're safe and understand what's unfolding."

The police said the first test of the warning system will commence on December 28 in preparation for the New Year's Eve celebrations.