On January 20 five people died in Melbourne’s Bourke Street when Dimitrious Gargasoulas allegedly drove through lunchtime crowds.

A sixth person died in hospital on Monday.

Speaking to Melbourne radio afterwards Mr Turnbull said people should look at heightening security in open areas.

“This is a very concerning vulnerability we have in anywhere where you have a large number of people gathered together, we need to be able to ensure as much as we can, that it is not possible to get a vehicle in there,” Mr Turnbull said.

The Prime Minister pointed to boosting the number of bollards, which prevented the Bourke Street driver from entering a certain area, as a measure to be seriously considered.

Wollongong City Council Lord Mayor Gordon Bradbery said this security issue in the mall and other public spaces was “on the radar”.

Cr Bradbery said the council was already instituting safety measures to protect the public at large gatherings.

“We were very conscious of that dynamic in recent times with Australia Day and New Year’s Eve events for instance, but we didn’t make a lot of public announcements about it,” Cr Bradbery said.

“We wanted people to feel safe.”

Cr Bradbery wouldn’t be specific on exactly what measures were introduced for those events.

“But it goes from everything from vehicle movements right through to, for instance the banning of alcohol, because there are just as many risks from intoxication as there are from other sources,” he said.

“We’ve got to look at the diverse range in which there are risks to public safety and manage them accordingly.”

The council was guided by police on what safety measures to undertake for each event.

In the wake of Bourke Street, Cr Bradbery said he did not want to “create undue alarm” and have people worry about their safety while visiting the mall.

“I don’t want people to think that could just happen in the mall – it could happen on a street,” he said.

“It’s one of those risks that we now have to live with and be very conscious of. It can happen at a pedestrian crossing, it could happen anywhere.”