Sirens have sounded four times in fire stations across Victoria to honour a group of fallen police officers, exactly one week after they were tragically killed in a truck collision on one of Melbourne's busiest freeways.

Leading Senior Constable Lynette Taylor, Senior Constable Kevin King, Constable Glen Humphris and Constable Josh Prestney died when a truck being driven by Mohinder Singh crashed into them just after 5:30pm on Wednesday last week.

The group were standing next to the Eastern Freeway after pulling over a Porsche driver, Richard Pusey.

The deaths have hit hard in communities right across Victoria, including emergency services families.

Today, at CFA stations across Victoria, wreaths were laid and a moment's silence was observed at 5:40pm, followed by the blasting of a siren each for the four fallen police officers.

Diamond Creek's CFA memorial was led by its captain, Peter Clarkson.

"It's a show of respect from the brigades to the police force. Our colleagues that we work close by in the emergency services," he said.

As well as volunteering at the CFA, Captain Clarkson has a daughter who volunteers at the CFA and a son who is a firefighter.

He said watching the news last Wednesday, his family was reminded of the sacrifice made by many in the emergency services community.

Loading

"It hit home that it could have been anybody," Captain Clarkson said.

"So with the news in the media, we've been talking a lot as a family.

"We just feel for the families of the victims."

Victoria Police in mourning

One week after the tragedy, the families of the four officers are preparing for their funerals.

Due to physical-distancing restrictions, the funerals will be small events, privately live streamed for family and colleagues, with a larger state event planned for after social-gathering restrictions ease.

Victoria Police employees are set to mark the closure of each private service with a minute's silence, including forming guards of honour outside their workplaces or sitting in their stationary vehicle with headlights on.

The Victoria Police Academy will also be lit up in blue from Thursday to Monday night to honour the members.

It follows magnificent scenes of buildings across Melbourne being illuminated in blue for the officers, including Parliament House and the National Gallery of Victoria.

Tributes are still flowing in large numbers on social media groups, with many sharing memories of the officers.

Just this afternoon, a former squad mate of Senior Constable King paid tribute in a post to "a real gentleman".

"He was just a top bloke all round who was always free for a chat regardless of the circumstances," the colleague posted in a public group on Facebook.

Many others are posting about switching their light bulbs at home to blue globes, in honour of the officers.

"We have changed the globes on the front of our house to blue and left them on at night this week," one person posted.

"Thinking of everyone involved in the tragedy."

In a post on social media, Victoria Police said members were touched by the tributes.

"Thank you to all our Victorian fire brigades who sounded their sirens at 5:40pm today in memory of our fallen officers," the post said.

"We're truly touched by this beautiful gesture."

A serving officer told the ABC she spent the afternoon at home in regional Victoria contemplating the loss of her colleagues.

"I spent four minutes sitting outside on my porch feeling quite alone, until I heard the local CFA sirens sound about 5km away," she said.

"This warmed my heart. There has been so much pain, and to see and hear this support for my blue family means so much.

"They deserve to be honoured and forever remembered."