THE young New Zealand man who survived a crash on a remote West Australian road that killed his two best friends took his own life before help could arrive.

It is believed Kadin Wallace was driving when his ute crashed and rolled on a stretch of gravel road on Friday night 400km southeast of Perth.

His two friends, Dylan Sherriff and Jeremy Vergeer, were fatally injured in the crash.

The men - who were all from Southland - were on a hunting trip.

Police said that Mr Wallace died of "injuries he did not receive in the crash". It is believed he killed himself.

Mr Sherriff's brother, Brett, told the Herald today that he did not blame anyone for what happened. "Kadin and Verg were two of my childhood friends.

I don't hold any bad feelings towards anyone."

He also spoke about his brother, a farmhand who, like Mr Wallace and Mr Vergeer, had lived in Australia for several years. "He was the best f***ing human you could imagine."

Relatives of Mr Wallace and Mr Vergeer did not wish to comment.

Mr Vergeer, who leaves behind a young son, became engaged this month. His fiancee, Lauren Withers, posted a heartbreaking tribute to him on Facebook yesterday.

The three young men, (from left to right) Kadin Wallace, Jeremy Vergeer and Dylan Sherriff were best mates from New Zealand. Photo / Facebook Facebook

"You were my soulmate, my best friend, my everything. The future seemed so promising for us and I struggle with the idea that it's now all just a beautiful dream I had.

"We really were both so unbelievably happy. I know [you're] here with me now, you will watch over me and your beautiful little boy who you loved so deeply."

Mr Sherriff and Mr Vergeer were to have been groomsmen for fellow former Southlander Rory Watt when he marries in Esperance in July. Last night he was mourning the deaths of mates he regarded as family. "They were my brothers, basically," he told the Herald.

"We all did everything together. They were just awesome boys."

They became best mates after they moved to Western Australia to work, Mr Watt said.

"I've been here for nine years and Jeremy said he wanted to come over. I contacted one of my old bosses and said, 'I've got a mate who wants to come over and work'."

Mr Sherriff followed afterwards, before Mr Wallace arrived.

Mr Watt did not want to comment on revelations Mr Wallace seemingly took his own life after surviving the crash.

Family members and friends are now gathering in Esperance, where a memorial service will be held for the trio tomorrow. Plans are being made to bring the men back to New Zealand for their farewell services.