You're not alone with a flutter today

Scores of Wairarapa office workers will today down pens for the annual Melbourne Cup horse race and office sweepstake.

Melbourne Cup frivolities attract many Kiwis usually averse to the sport and unaccustomed to waging a bet.

The cup day, celebrated as a public holiday in most of Victoria, is the single biggest betting day for TAB in New Zealand.

It also turns thousands of workers into makeshift bookies as workplaces join in the fun by offering up an office sweepstake.

The Department of Internal Affairs warns prize money from office sweepstakes cannot exceed $500. This means tickets for the 24-strong horse race can cost no more than $20.83, a spokesman said.

Any money raised must be returned as prizes and no one is allowed to profit from organising the sweepstake.

Violating these regulations could incur a fine of up to $1000.

And beware of offering prohibited prizes. Firearms, liquor, tobacco and vouchers for sex services are all out of bounds.

About 30 people are expected to watch the race at the Carterton Memorial Club.

Festivities will kick off about 4pm, with $1, $2 and $3 sweepstake tickets on offer.

President Martin Keedwell said head-gear was of the utmost importance at the gathering.

"We've got prizes for people wearing the best hats.

"So if you want to come along then wear a hat," he said.

Kiwi punters are expected to bet about $8 million on today's Melbourne Cup. One of the largest bets placed yesterday was for $5000 on Australian horse Ethiopia, a TAB spokesman said.

"If it wins, the lucky punter will stand to get something in the vicinity of $100,000."

In 2011, 14 per cent of Kiwis aged over 18 placed a TAB bet on the cup race.

This year, four New Zealand-bred horses will line up at 5pm to compete for the $7.77 million prize money. Kiwi horses Maluckyday, Lights of Heaven, Precedence and Zabeelionaire are among 24 stayers entered in today's race.

Sweepstake rules:

Prize must not exceed $500

Any money collected must be returned through the prize

Prohibited prizes include:

Firearms; Liquor; Vouchers for sexual services; Tobacco products

Source: Department of Internal Affairs

Winning tips

The race has been won most often (44 times) by a horse aged four years

The most successful sex is "entire", aka a male horse which has not been desexed (64 wins)

Numbers 4 and 12 are the luckiest numbers (11 wins each)

The race has been won six times each by horses starting the race from barriers 5, 10, 11 and 14

Jockeys wearing predominantly black or royal blue have been the most successful