He had been working delivering cement to ports and had recently completed his Able Seafarer Certificate before he died.
Solomon said Johnston and his girlfriend were travelling along the road when a vehicle approaching on the wrong side of the road forced them to swerve.
Their car hit a tree killing Johnston and causing his girlfriend minor injuries.
"Both families are devastated with the loss of Kaine at a time of his life where he was definitely making his mark. He will be missed by all for a long time," Solomon said.
Johnston's funeral would be held at his whanau's marae, Takahiwai Marae in Ruakaka.
"He's meant to carry us in there. Not us carry him."