Cairns said people at the scene would have seen the motorcycle, but no one had come forward with information so far.
"This is a tragedy that has happened to this young man, and police are trying to establish the events that led up to his death."
Cairns said it was too early to know how the man died or whether there was a gang element. He said police also did not know the make and model of the motorcycle he was riding.
The Rotorua Daily Post went to the scene of the crash yesterday.
Skids and police markings formed a line from State Highway 38, past a tree and pile of rocks, across an intersecting road and traffic island, and finished in long grass near the Kopuriki Rd intersection.
Bright orange spray circled parts of the motorbike, including steel fittings, parts of lights and a coil.
A white truck was parked beside the marks in the grass, and five glass beer bottles had been placed upside down in the dirt there.
Neighbours told the Rotorua Daily Post they "didn't hear a thing" at 6.35pm on Sunday when the man crashed.
One said, "I don't consider it a dangerous corner".
"I had just got back from getting fish and chips in town. I just saw a cluster of police cars and a lot of locals there. I didn't know the boy."
03/02/19 18:24: Traffic incident in Murupara. 1 patient. No transport. https://t.co/5OXIeuftX2
It is the second motorcycle fatal crash at the weekend in the region after a man died at Tauriko in Tauranga near the intersection of Sycamore Rise and Cambridge Rd at 4.30am on Sunday.
Eleven people were killed in road smashes in the Rotorua district alone last year.
The toll shot up from just four deaths in 2017.
It was a bad year for the entire Bay of Plenty in 2018, with 51 road deaths, compared with 47 in 2017 and 46 in 2016.
Anyone with information about the State Highway 38 crash is urged to contact Murupara police, Rotorua police or the anonymous Crimestoppers line on (0800 555 111).