School organisers are devastated after a motorcyclist died during Otago's Lake to Sea Trail Bike Ride near Milton yesterday.

The 18th fundraising event for Tokomairiro High School ended in tragedy when a rider had a fatal accident during one of three crashes.

PTA chairwoman Lynne Johnston says everyone's hearts go out to the man's family and friends.

She says the school's focus is to support the family and those affected by the tragic incident.

Two other motorcyclists - among 870 riders - had to be airlifted to hospital after single bike accidents.

Police have referred the death to the Coroner.