ELECTRIC ENTERTAINMENT: Kieran McAnulty, pictured at the opening day of this year’s Golden Shears at the War Memorial Stadium in Masterton, says the event is ‘‘shearing’s Wimbledon’’.

Bets are pouring in for this weekend's Golden Shears in Wairarapa, the world's only sports-shearing bookie says.

Early flutters on the 54th Golden Shears, known as the world's biggest shearing competition, indicated it would be one of the most hotly contested, said the TAB's Kieran McAnulty.

Mr McAnulty, who has set the odds on sport-shearing for the TAB since 2010 and is also the Golden Shears master of ceremonies, said the TAB decided to open a comprehensive book on the Golden Shears when it realised its "mystique" was transcending its original, rural audience.

"It's the Wimbledon of shearing. A lot of people in cities might not totally understand the sport aspect of it, but they'll appreciate how entertaining the event itself is."

Golden Shears organising committee member Greg Herrick said the atmosphere at Masterton's War Memorial Stadium on Saturday night would be "electric".

"We've been in here sometimes and the roof's nearly come off . . . it's like they're engaged in a duel, going blow for blow."

Around 480 professional shearers from as far away as France and the USA will compete. While top shearers shear a sheep in about 40 seconds, scoring is not just on speed, but also quality.

Mr Herrick said the complex scoring system was explained through live commentary.

"They're dripping with sweat, there's intense concentration . . . it's just amazing."

The TAB returns one per cent of its turnover on the Golden Shears and five per cent of its profit to Shearing Sports New Zealand, TAB spokesman Grant Nisbett said.

He expected more betting on Golden Shears than on the New Zealand Golf Open, also on this weekend.

The biggest bet so far was an unsuccessful $5000 punt in 2011 on 16-time winner David Fagan, a favourite again this year, and the biggest win was "upwards of $10,000" in 2012.

Last year 18,000 people watched the final on live streaming and 5000 attended over the three days, Mr Herrick said. He estimated the event brought $1 million into the region annually, with 60 per cent of tickets sold to people from outside Wairarapa.