Victoria's parliament is marking the 50th anniversary of the West Gate Bridge disaster, the state's worst industrial accident.
On October 15 1970, a 112-metre span of the partially-constructed bridge collapsed, killing 35 workers and leaving 18 others seriously injured.
On Thursday, both houses of parliament held a minute's silence at 11.50am, the time of the accident, while building sites around the state came to a halt and cranes sounded their horns.
The flags on top of the West Gate Bridge will be at half-mast until 7pm.
Premier Daniel Andrews' daily media conference started at 11.51am as a tribute to the victims.
"A section of the bridge, supposed to be a beacon of modernity and cutting-edge design, collapsed and in amongst that chaos, the flames, the smoke, the heat, 35 Victorians lost their lives," Mr Andrews said.
"It also left a scar on our city. For many years after, parents crossing the bridge would tell the kids of that terrible tragedy, mine included.
"From the rubble, ash and heartbreak though came something - an understanding that every worker matters and every workplace should be safe."
He added the tragedy came to define the state's occupational health and safety laws.
Roads minister Ben Carroll said 88 children lost their fathers and 28 women became widows.
Workplace Safety Minister Ingrid Stitt said it was important to remember the tragedy as the state embarks on a number of new infrastructure projects.
"We all (should) refocus our commitment to making sure that every Victorian worker comes home to their families safe every day," she said.
Animal Justice MP Andy Meddick has staged his own memorial in the parliament's Queen's Hall, with 58 white roses representing those killed and injured.
Handwritten notes will display the names and professions of the victims.
"It's extremely important that we remember the worst industrial disaster that this state, that perhaps this country's ever seen, because it was seminal in how this country and how the state then dealt with the rights of workers going forward," Mr Meddick told reporters outside parliament.
"So many of the strides that the union movement has made in the rights of workers, in all workplaces stem from that moment. And it certainly changed the construction industry I worked in for 20-odd years."
Construction union boss John Setka said his father was lucky to survive the accident, riding the bridge as it crashed down.
"We've come a long way when it comes to enforcing safety on worksites, but the enormity of this tragedy will never be forgotten," he said in a statement.
A commemoration at the West Gate Memorial Park in suburban Spotswood, near the site of the accident, to mark the milestone anniversary is on hold because of Melbourne's coronavirus restrictions.
Mr Setka will head to the site with his father and son to lay a wreath.
The park was opened in 2004 to honour the victims and to increase awareness of workplace safety.
The Victorian Trades Hall hosted an online tribute on Facebook.