"We believe that Mr Mackenzie collided with a fence at around 4.15am this morning and has died instantly.
"He was found around 6am by a family member who had gone out looking for him. That person commenced CPR, but he was confirmed dead at the scene by attending medical staff," said Kerrisk.
The motorcycle involved in the crash was an off-road dirt bike.
"Sadly, speed and alcohol are factors that we believe have contributed to this crash, and we have confirmed a crash helmet was not being worn by the rider. This is a tragic loss for the family and an avoidable loss of life," Kerrisk said.
"Alcohol is the second biggest contributing factor to road crashes in New Zealand. Even small amounts of alcohol begin to impair your ability to drive as it slows your reaction times and affects your senses and judgment."
Police and Victim Support were supporting Mackenzie's family.
The investigation is ongoing and anyone who has information that can assist is asked to contact Cromwell Police at 03 445 1999.