Anti-war protesters staged a third straight day of demonstrations opposing the the Land Forces weapons expo held at the Melbourne Convention and Exhibition Centre.
Police were out in force early on Thursday, maintaining no-go lines near the convention centre ahead of visitors to the expo arriving, as "defiant, determined and impassioned" demonstrators returned, although the scene remained peaceful.
"Despite the incredibly shocking violence that people encountered yesterday, hundreds turned out again to confront the arms deals going down at Land Forces," organiser Caroline Da Silva said.
Victoria Police arrested five men and seized bottles of red paint, marbles and bags of small rocks used to create obstacles for the police horses.
Detectives are also investigating after a man was allegedly assaulted and had urine and faeces tipped on him as he tried to enter the expo.
City workers faced disruptions to their commutes home after hundreds of protesters picketed outside the offices of defence contractors Hanwha Defence and Elbit Systems blocking access to cars and trams along Bourke Street.
"It is the primary provider of death and destruction to the Palestinian people," rally speakers said.
On Wednesday, protesters set wooden pallets on fire in the worst day of action outside the venue. (Con Chronis/AAP PHOTOS)
Police Minister Anthony Carbines said peaceful protesters who were caught up in violence at the rally "only have (themselves) to blame".
"It would be naive to think that if you've got yourself caught up in troubles down there, then you have probably put yourself in the wrong place," Mr Carbines said.Â
Violent and chaotic confrontations between protesters and police broke out on Wednesday, with 42 people arrested and charged with assaulting, hindering and obstructing police, arson and blocking roadways.
Wheelie bins were set alight and thrown towards police barricades, while horse manure, food-grade acid, glass bottles and baked bean can "missiles" were launched at officers.
Riot officers returned fire on the 1500 demonstrators with rubber bullets, tear gas and flash-bang devices.
The protests began on the eve of the expo on Tuesday and are expected to continue until Friday. (Joel Carrett/AAP PHOTOS)
Police said 27 officers were treated for minor injuries, while Ms Da Silva said there were eight to 10 times the number of activists injured in the melee.
Protesters say weapons on display inside the convention centre have been used on civilians in the Gaza conflict.
Police Commissioner Shane Patton lashed out at "hypocritical" anti-war protesters warning the largest deployment of officers in two decades will be prepared for any event for the duration of this the conference.
Premier Jacinta Allan said she was particularly concerned to hear some protesters had come from interstate.
"When you come ... to protest carrying rocks, carrying bottles and balloons filled with urine ... your intent is not to peacefully protest ... indeed your motives are exposed," she said.
Federal government minister Tanya Plibersek slammed the "disgraceful" violent protesters.
Thursday's protests were "generally" less volatile than on Wednesday. (Con Chronis/AAP PHOTOS)
"I don't know how you call yourself a peace protester and turn up and start throwing missiles at people who are just out there doing their jobs," she told Sky News.
Mr Carbines said protesters' behaviour on Wednesday was on a separate level to regular marches which have opposed the war in Gaza.
"There's protest activity, then there's just bar brawls and thugs, and that's what we saw yesterday," he said.
Opposition leader John Pesutto called for police to have wider powers to move on protesters and compel them to remove face coverings, amid what he described as the "normalisation" of protest violence in Victoria.
