Police are pleading with drivers to take care after a “heart-breaking” crash killed three brothers and another man in Western Australia.

One of those who died was a nine-year-old boy.

Police believe a silver Nissan Navara utility was travelling east on the Great Eastern Highway in Clackline, about 80 kilometres north-east of Perth, when it lost control and hit a tree about 12.30am on Friday.

The 20-year-old driver died, along with his brothers – the young boy and a 19-year-old. A 45-year-old man, described as a family friend from NSW, was also killed.

“My heart goes out to the families when you lose anyone in a crash. But when you lose three young men in the prime of their lives and a friend, this will have lifelong impacts for that family, for their friends, and for our community,” Western Australian Police superintendent Gene Pears said.

“This is a heartbreaking incident for WA.”

Major crash experts were examining the scene on Friday. Support has also been offered for first responders, including young police officers.

“I attended the scene this morning and, as you can imagine, it was a very confronting scene for first responders to attend and investigate,” Pears said.

“[This is] some of the more confronting stuff that as a country police officer, particularly a young country police officer, that you can see absolutely coming across. Something that’s so immediate, it’s heart-breaking.”

Pears urged drivers to take care, particularly at night and on longer trips.

“It’s so important to drive to conditions, you know, particularly in the country at night, in the early hours of the morning with those factors … around fatigue, road conditions, seatbelts, all those sorts of things,” Western Australian Police superintendent Gene Pears said.

“They’re so critically important. I can’t stress that enough … [It’s] unimaginable that you’ve lost three brothers.”

Anyone with dashcam footage or who saw the ute travelling in the area before the crash is urged to contact Crime Stoppers.