An organiser of powerboat races in the Bay of Islands on Saturday says elaborate plans are in place to protect bottlenose dolphins.
Massey University researchers say the two races being held by New Zealand Offshore Powerboat Racing at Paihia's Te Ti Beach coincide with the peak calving season for bottlenose dolphins, which puts them in danger.
An organiser of the event, Noel Brown, says a detailed protection plan is in place and the competition will be cancelled if the dolphins are on the course.
He says 15 patrol boats, two helicopters and dolphin cruise ship skippers will all be patrolling the course.
The director of the university's coastal-marine research group, Karen Stockin, says the the "equivalent of Formula One on the water" could not have come at a worse time.
Dr Stockin says six newborn bottlenose dolphins have been observed in the Paihia area in recent weeks, and the risk of the mammals being injured during the high-speed races is exceptionally high - and if the expected numbers of spectator boats turn out on the water, they'll have little refuge.