Police have warned the public against blocking speed cameras after a West Australian woman allegedly parked in front of a Multanova speed camera. 

Officers were called to Sandford Road in Albany, 418km south of Perth, on Saturday and spoke with a woman who had parked a four-wheel drive next to a speed camera operator's vehicle. 

The woman also allegedly held a sign warning passing motorists of the camera. 

Albany police station officer in charge Senior Sergeant Carlos Correia said they were investigating the matter.

Senior Sergeant Correia said it was an offence to block a speed camera. 

"If he or she parks a car that prevents the camera person from doing their job, as in getting pictures of speeding cars, yes it's an obstruction," he said.

"People may be charged with obstructing police."

Obstructing police can lead to a fine or prison time of up to three years under WA law. 

Senior Sergeant Correia reminded the public that speed camera operators were simply doing their job and were not to be harassed.

"They're employed to do it, they do it without issue, we don't want them hurt or things thrown at them or people stopping to abuse them," he said.

Are speed camera warning signs legal?

Members of the public have displayed signs warning other drivers of a speed camera ahead across Australia in recent years, with social media groups also posting camera locations.

Senior Sergeant Correia said a member of the public could hold a sign alerting other drivers to a speed camera ahead as long as they did not interfere with the operation of the camera. 

"The only issue is if they interfere with the operations of the camera person, like getting close enough to prevent the camera operator doing their job.

Can you flash your headlights to warn drivers?

Senior Sergeant  Correia said flashing lights to warn motorists of a speed camera could be breaching road rules, but police would apply common sense.

He said that technically, flashing high beam lights within 200 metres of an oncoming vehicle could draw a fine of $100 and a demerit point. 

"You can be subject to a fine but common sense comes into it, there could be a number of reasons drivers flash their lights," Senior Sergeant Correia said.

"There could be a crash or a kangaroo on the road ahead."

Senior Sergeant Correia said flashing another motorists to warn them of a speed camera could draw a fine. 

Emergency services witness toll of speeding

Senior Sergeant Correia said the easy way to avoid a speeding fine was to slow down.

He said emergency services witness the carnage of speeding and it takes a toll.

"For any emergency service personnel who go to fatal or serious crashes and see what we see, once you see it you can’t unsee it," he said.

"We've seen what speeding can do. The message from us as a collective is just slow down, avoid the fines. The ultimate way of not getting caught speeding is, do the speed limit."