A car-dooring that allegedly led to the death of a cyclist on a notorious Melbourne road has revived warnings from bicycle advocates that motorists are not paying enough attention.

The 25-year-old Italian cyclist was cycling south on Sydney Road in Brunswick just after 4:00pm when a person in a parked car allegedly opened their door, knocking him onto the road.

The cyclist was struck by a passing truck and died at the scene, police said.

Bicycle Network Victoria (BNV) spokesman Garry Brennan said while the majority of motorists were becoming more aware about the dangers of dooring cyclists, some people were ignoring the safety messages.

"We're optimistic that we're getting on top of the dooring problem, but you can never relent for one moment," he said.

"There are thousands and thousands of people getting in and out of cars, and they're simply not paying enough attention."

Sydney Road is a notorious stretch of road for cyclists, who must navigate trams, cars and pedestrians.

It has one of the highest accident rates for cyclists in the state, prompting police and VicRoads to conduct an "enforcement and awareness" campaign over the summer.

Senior Constable Sarah O'Keefe said road users needed to be more aware of each other.

"We have been working tirelessly trying to get that message across," she said

But Victorian Greens Leader Greg Barber said Friday's fatality highlighted the need for a better campaign to raise awareness of driving safely around cyclists.

"Unfortunately these type of accidents happen all the time," he said.

"The official figures show about three serious accidents a week involving a car door, but that's really just the tip of the iceberg as any cyclist will tell you."

'Unfortunate' Sydney Road upgrades were not made sooner: BNV

Sydney Road has one of the highest accident rates for cyclists in the Victoria. ( Supplied: Bicycle Network Victoria )

Last week, the State Government announced a $1.6 million package to make riding and walking along the road safer.

The package includes banning right turns at 17 intersections and increasing off-street parking to reduce the number of doorings.

Mr Brennan said the work should be completed next year.

"[Sydney Road] is a risky area for bike riders and for pedestrians, but the plans are already underway and it's unfortunate that we couldn't get this work done earlier," he said.

Floral tributes have been placed at the scene of the fatality.