A St John spokesman said three ambulances were sent and took two patients to Dunedin Hospital in a moderate condition.
A police spokeswoman said the incident happened at 4.10pm on the Allanton-Waihola Rd (State Highway 1).
Three bikes slid off the road and there was possibly a vehicle involved.
Fire and Emergency New Zealand arrived about 4.10pm and police about 4.30pm, the spokeswoman said.