One person has died and another eleven people are injured after crashes at the Lake to Sea Trail Ride near Milton today.
Emergency services responded to the crashes after two distress beacons were activated in the area at around 12.10pm.
A St John spokeswoman confirmed that a total of eleven people were injured at the event, with five hospitalised.
Two were flown to Dunedin Hospital, one in a serious condition, the other moderate.
The Lake to Sea Trail Ride is a motorcycle and ATV event through forestry areas and farmland between Milburn and Toko Mouth.
The event is in its 18th year and is a fundraiser for Tokomairiro High School.
A reporter at the scene said 870 participants set off on ATVs and trail bikes from Milburn at 9.30am.
The riders took three separate trails, one for advanced riders, one for open riders and one for junior riders.
After two hours the trails met at Crystals Beach, where there was lunch, then riders travelled the length of the beach and returned to Milburn via the loop trails.
The reporter said the conditions were warm and windy for the most part. It was wet underfoot in the forest and the trails there were slippery and muddy, he said.Before he left the event at 2pm - the last riders came in after 3pm - he had only heard of one incident, in which a person received deep lacerations to the leg, at a place called Westerns Beach.
There was no indication anything else untoward had happened, he said.
"Everyone was telling me they had a great day."
Clutha Mayor Bryan Cadogan has voiced his support for the family and friends of those affected by the "devastating" outcome of the event.
"My thoughts go out to the family and friends," Mr Cadogan said.
St John were in attendance at the event.