Racing on the opening day of the Sail Grand Prix has been cancelled after a prolonged period of dolphin activity on the racecourse.

Despite delays to racing to let the animal pass, the dolphin remained on the racecourse for the duration of the race window at Lyttelton Harbour.

Ahead of the event, SailGP developed a mammal management plan for racing in Lyttelton Harbour.

The protocol demands that racing is stopped when a dolphin is sighted near the racecourse and will not resume until at least 20 minutes have passed since the animal was last seen within the shutdown zone.

Speaking about the cancellation, SailGP managing director Andy Thompson described it as ‘a tough day for the league and our super passionate Kiwi fans.”

“The athletes were ready to go and the conditions were epic and we were looking forward to some really fast racing. The conditions are looking really top end for tomorrow so hopefully the F50s will be out there ripping around and we can send the fans home super happy.”

It comes after the 10-strong fleet took to the water for practice racing on Friday, with three races.

Crews struggled to keep the F50s under control as gusty winds buffeted the course, and a collision between Emirates GBR and Spain earned the Brits an 8-point penalty.

The second day of the ITM New Zealand Sail Grand Prix will kick off at 15:00 NZDT on Sunday.