Additional bollards will be installed in Melbourne's Bourke Street mall to create pedestrian refuges beside tram tracks in case of another vehicle attack.

The work is part of ongoing security upgrades across the city, sparked by a January 2017 murderous rampage by James Gargasoulas.

Gargasoulas mowed down and killed six pedestrians and injured dozens others along the popular shopping strip.

“Following advice from our security experts, we’re now putting in some additional bollards running down the tram line area,” Police Minister Lisa Neville told reporters on Wednesday.

“These are about providing protective pedestrian zones, providing a safer area, a place where people can take refuge in case of a hostile vehicle attack.”

Additional “street furniture” and planter boxes will also be installed to maintain the area’s amenity, Ms Neville said.

The work will start in July.

Stainless steel bollards and reinforced barriers have been installed on Princes Bridge and at neighbouring Flinders Street Station as part of the security upgrades.

Completion of works at Federation Square is delayed because of construction for the Metro Tunnel railway, but other measures are on track, Ms Neville said.

Extra CCTV and an emergency speaker system have been installed.

Melbourne’s underground train network will also soon get high-tech cameras that will feed directly to Victoria Police to help monitor the network and potential threats.