A month before the collision, Fafita's licence was suspended following an incident where he was found asleep in a vehicle with the engine running in Auckland.
After finishing work on May 3, the three men purchased and consumed alcoholic beverages before driving their work vehicle, a Ford Transit van, to Taupō.
Between about 9.40pm and 4.10am on May 4, the van was parked at an address on Roberts St before the group travelled to McDonald's.
Fafita was driving when they left the establishment at 4.18am. Takau was in the front passenger seat and Koloi was seated in the rear.
The men were travelling along SH1 when about 4.45am they were involved in a head-on collision with a truck and trailer unit driving in the opposite direction.
Coroner Michael Robb's report said a vehicle behind the truck unit witnessed the collision and contacted emergency services immediately.
"Emergency services confirmed that two of the van occupants had died, likely on impact," Coroner Robb said.
"They were later identified as Viliami and Joseph. The third, later identified as Siale, was transported to hospital via ambulance but sadly died en route.
"The driver of the truck and trailer unit was transported to hospital with a broken wrist, cuts and bruises."
Coroner Robb said there were aspects of the incident that suggested fatigue was a factor in its cause, with Fafita awake for more than 12 hours.
Inattention and/or distraction were also considered in Coroner Robb's report and could not be excluded as factors.
Slow response to lane deviation was also likely, with alcohol known to exacerbate the effects of fatigue.
The legal limit for a New Zealand driver 20-years-old or over is 50 milligrams per 100 millilitres.
Post mortem results showed Fafita had a blood alcohol level of 185 milligrams per 100 millilitres.
Koloi's was 79 milligrams per 100 millilitres and Takau's 202 milligrams per 100 millilitres.
No other drugs of relevance were detected, Coroner Robb said.
"Coroners, police, and NZTA have consistently highlighted the dangers of driving while fatigued and/or under the influence of drugs and alcohol and the risks that this poses," he said.
"There have been numerous publicity campaigns highlighting those risks. In that context, I make no additional comment or recommendation."
Fafita died from head, chest and multiple injuries due to high-energy impact sustained in a head-on collision.
Takau died from head and limb injuries due to high-energy impact sustained in a head-on collision.
Koloi died from hypovolaemic shock with bilateral femoral fractures due to high-energy impact sustained in a head-on collision.
