It's Cup Day in Christchurch and more than 20,000 punters are expected at Addington Raceway.
The New Zealand Trotting Cup is the centrepiece of Cup & Show Week, which also features a visit from Prince Charles and the Duchess of Cornwall on Friday.
Fifteen starters will compete for the $600,000 prize purse in the Cup Race over 3200 metres.
The current favourite is last year's winner, Terror to Love, with strong support also for Franco Ledger and Caribbean Blaster.
The weather is forecast to be cloudy with morning showers and a high of 13 degrees.
The race is due to start at 5.15pm.
Police say they will take a tough line on alcohol-related behaviour. Liquor ban areas will be vigorously patrolled.
Last year, a drunk woman removed her clothes and ran across the track, causing a race to be delayed.