Fascinators, heels and colourful suits de rigueur at Christchurch's Cup day

The fascinators, colourful suits, and high heels were out in force in Christchurch today as about 13,000 people headed to Addington raceway for Harness Racing's biggest day, IRT New Zealand Trotting Cup Day.

The day is also the TAB's biggest betting day within New Zealand, and by late afternoon the meeting had a turnover of $3.9 million, up on last year's turnover by around 4 percent.

With temperatures up to 25C in Christchurch and a warm nor-west wind, one of the biggest challenges was keeping cool.

Especially for punters like Caleb Adam, Jody Mills and Brad Wilson, who were wearing specially imported suits.

They are regulars at the event and say they have a simple goal for their clothes choices - standing out.

Caleb Adam sported a colourful paint splatter suit, Brad Wilson was in a green suit with a gambling theme, and Jody Mills went for his children's favourite - SpongeBob SquarePants.

It was also a day for people to bring out their finest frock and fascinator. Steph McGreavy and Kit Winter-Davies, from Timaru, were adorned with handmade felt fascinators made by Steph.

She said she took up the hobby during the lockdown, and even creating the horses was not as tricky as it looked.

She carefully chose the designs to match her and Winter-Davies' dresses for the day.

Addington Raceway chief executive Brian Thompson said they had already bought 10,000 bottles of water to hand out in a bid to help people stay hydrated, but when they saw the forecast hot weather they upped that to 15,000.

One person who had dressed for the weather was Stewart Curtis, who went with the brave choice of a shirtless suit look.

He said the shirtless look had always been his plan, and was delighted the weather was playing ball.

For horse trainer Graham Court, in town to race his horse, Straight Flush, who was running in the second race, the day is all about the racing.

He said the Cup Day was the biggest day of the year for people in his industry.

"It's huge. It is THE day in harness racing New Zealand is New Zealand Trotting day."

By late afternoon police said the crowd had been relatively well behaved, but were warning people to take care when they left the site after the final race.

And the final result - Australian raider Swayzee, driven by Cam Hart, won the New Zealand Trotting Cup.

Swayzee beat the New Zealand favourite Akuta driven by Mark Purdon by three lengths with Beach Ball third.

Police said they arrested one person for disorderly behaviour at Addington Raceway today and issued warnings to six others.

Police say most of the 13,000 who attended were well behaved.

The person arrested was a 31-year-old man who was charged with disorderly behaviour and resisting arrest.