Electronic speed signs will be implemented at the Ecklin South junction.

The signs will be triggered by sensors that detect cars approaching on the side road, Ayresford Road, temporarily reducing the speed on the Cobden-Warrnambool Road from 100km/h to 70km/h until the car is able to turn.

The reduced speed limit will only stay active until there are no more vehicles waiting to turn onto the Cobden-Warrnambool Road.

Roads Minister Jaala Pulford visited the intersection, where there have been serious injuries recorded, including a man who was left with a severe brain injury after an accident in 2011.

"It's a very busy intersection," she said.

"The line of site isn't great and there are lots of cars whizzing past. We've had reported crashes there with serious crashes. Having stood there and had a look I can see why it had been identified very early for this new tech. They are very clear."

She said the side road activated speed technology had proved effective in New Zealand.

"They have been doing it for a while," she said.

"A similar program over there reduced serious and fatal crashes at intersections by 89 per cent since 2012."

She said the signals were new to the Victorian road network and the first signs had been installed at Dunkeld.

"Around 70 per cent of our fatal intersection crashes in regional Victoria are on high speed roads," she said.

"Being able to slow people down at the intersection is an innovative solution."

South-west police road safety adviser Senior Sergeant Chris Asenjo said a number of initiatives were raised at a community forum in Portland last Thursday.

He said one of those initiatives was variable speed zones depending on traffic or weather conditions.

"We'll support almost anything that can reduce road trauma and make the community safer," he said.

"There will never be enough money to fix every problem with all the roads so we need to look at everything we can to reduce road trauma. It would be far better to have to reduce your speed, (and it) cost a few seconds than to cost you your life."

Senior Sergeant Asenjo said police would enforce changing speed zones.

"Changing speed zones are not new," he said. "We've got reduced speeds at railway crossings and in school zones. It's just an extension of the technology that's available. But such initiatives will only work if drivers obey the rules and travel at the legal speed limit."