A man died and many more people were injured after emergency services attended three separate road incidents in the region on Good Friday.

Ararat Sergeant Mario Miocic said it was disappointing to see so many incidents in one day.

"It was still early days of the weekend," he said.

He said many people would be travelling along the highway again on Monday.

Sergeant Miocic said people had to be careful on the roads.

"Stay safe, be aware and don't speed," he said.

A South Australian man, 55, died after a single-vehicle incident on the Western Highway at Armstrong, between Great Western and Ararat, on Friday morning.

A police spokeswoman said a passer-by called emergency services after coming across the crash scene just after 6.30am.

"Investigators believe the east-bound vehicle crossed onto the wrong side of the road and crashed into a tree," she said.

"A man, thought to be a front-seat passenger, died at the scene." The spokeswoman said a South Australian woman, 56, was flown to hospital with leg injuries.

A girl, 16, who was the backseat passenger, was taken to hospital in a stable condition with injuries to her chest, abdomen and pelvis.

Emergency services were then called to a four-car incident on the Western Highway at Ararat just before noon on Friday.

The spokeswoman said there was a nose-to-tail collision between three cars, which were travelling west in congested traffic over a slight rise.

She said following that, a third vehicle then veered onto the incorrect side of the highway and allegedly crashed into an oncoming east-bound car.

"Occupants out of east-bound vehicle, a man and a woman, have both been conveyed to hospital with serious injuries. A male driver of third car also conveyed to hospital with non-life threatening injuries."

About an hour and a half later, emergency services were called to a third incident in the area.

A woman and two children were taken to hospital following a single-vehicle crash at Warrayatkin Road, Ararat.

"The woman was travelling along Warrayatkin Road about 1.25pm when she swerved to miss a kangaroo and struck a tree," the police spokeswoman said.

"The Adelaide woman and two children were taken to hospital with non-life threatening injuries."

An Ambulance Victoria spokesman said the woman, in her 30s, was taken to Ballarat Base Hospital with back injuries.

He said the two children, a female infant and male toddler, were also taken to hospital with cuts and abrasions.