About 10,000 people have arrived at Addington Raceway in Christchurch so far for Cup Day, the city's biggest social event of the year.
The first race started just after midday and fans are looking forward to the main event, the New Zealand Trotting Cup at 5.15pm.
There is added interest this year as pacer Terror to Love looks to make it four cups in a row.
Race organisers said if this happens Addington will open the gates to all and provide free entry on Show Day this Friday.
The race is offering $700,000 in prize money, making it the richest standing-start harness race in Australasia.
A crowd in excess of 20,000 race-goers is expected and forecasters are predicting mainly fine weather with a northwester.
Fashion will play a big part of the day with the traditional fashion in the field contest sure to be keenly contested.
This year's guest of honour is the Australian spin bowling great, Shane Warne who race organisers say loves a punt on the ponies.
In previous years the day has been marred by drunken crowds, and police in Christchurch said they were expecting to be kept busy this evening as crowds of race-goers move from Addington raceway to the city's bars.
Deployment manager Inspector Peter Cooper said police will be increasing patrols from mid-afternoon and visiting licensed premises around Addington Raceway and the Lincoln Road/Addington area.
A temporary liquor ban is in place from 9am to 10pm and covers several streets in the vicinity of the race course.
Anyone breaching this and existing liquor bans can expect to be prosecuted.
Typically the busiest times for police call-outs for disorder and violence are between 5pm and 10pm with the total number of calls more like those for a typical Saturday night in Christchurch.