St John was referred to as to Meremere, the place an NZ Jetsprint Championship spherical was happening.
A jetboat accident within the north Waikato severely injured two individuals.
St John despatched two helicopters and two ambulances to a jetboat crash close to the Meremere Dragway round 2.10pm on Saturday.
Meremere was internet hosting the fifth spherical of the NZ Jetsprint Championship on Saturday, in accordance with the NZ Jetsprint Association website.
St John was on the scene simply after 2.40pm, a spokesman stated.
Two sufferers have been assessed as being in critical situation and have been flown to Waikato Hospital.