A fifth of Victoria's emergency service workers have had multiple near misses with speeding cars when helping people at accidents and emergencies.

These "often unrecorded" near misses have prompted the government to introduce a new 40km/h rule for cars passing emergency vehicles stopped with flashing lights or sirens sounding.

From July 1, drivers who fail to slow down face a fine of $277 or a maximum court penalty of $793, the state government said on Monday.

"We're making these changes so they can do their job without fear of being injured or killed by a passing vehicle," Ambulance Minister Jill Hennessy said.

Roads Minister Luke Donellan said emergency workers have told the government they "feel in danger while they're doing their job".

A recent survey found almost one-in-five emergency service workers said they'd had four or more near misses while stopped on the roadside over the past three years, Mr Donellan said.