Big bets start flowing as bookmakers hope for lucky Melbourne Cup day

Australia's bookmaking giants are bracing for their busiest day of the year, with some Melbourne Cup bets placed early in the day giving hope they might buck a decline in wagering turnover so far this racing season.

Betting turnover has been down during this year's spring racing carnival - with turnover on the Caulfield Cup on October 19 falling $31.4 million, or 24.6 per cent - and all eyes will be on whether domestic betting on the Cup falls below last year's figure of $312 million.

Not everyone has been turned off, however, with the country's largest bookmaker TAB reporting these significant bets on the Melbourne Cup placed on Tuesday morning:

$10,000 @ $9 Mer De Glace
$8,000 win / $7,000 place @ $26/$7.25 Master Of Reality
$7,000 @ $8 Finche $3,500 @ $9.50 Constantinople
$2,500 @ $101 Sound

TAB's biggest bet on the cup so far is $10,000 for Surprise Baby to win, placed at odds of $26 on October 4 - meaning that hopeful punter will get a quarter of a million-dollar payout if the Kiwi horse crosses the line first.

Sportsbet said on Tuesday morning it expected to take more than 5 million bets on the Cup, at a rate of more than 35,000 bets per minute in the lead up to the barriers opening.

The online bookmaker said it had made "significant investment" in its online platform to optimise "speed, performance, scale and resilience", which follows it, Ladbrokes and online betting exchange Betfair all experiencing tech crashes in the lead-up to last year's race.

Sportsbet chief executive Barni Evans told The Age and The Sydney Morning Herald last week there was "a decent chance that turnover will be softer" at this year's cup.

The decline in wagering has been partly blamed on new point of consumption taxes levied on online bookmakers.

Those state-based taxes of 8 to 15 per cent has reined in on Sportsbet, BetEasy, Ladbrokes and other online bookies' profit margins, making it harder for them to offer attractive odds and special offers, which in turn has made it less attractive for punters to gamble.

Along with the new taxes, Mr Evans said betting turnover was being driven lower by a string of unfavourable race results for punters, causing customers to either be reluctant to bet or run out of money earlier in the day and so bet less in total.

TAB owner Tabcorp's managing director of wagering, Adam Rytenskild, said consumer spending was tightening in general which flowed on to gambling, while competition between the bookmakers was not accelerating at the same pace it was a year ago.

"The markets totally changed - marketing strategy has changed, pricing has changed, customer experiences have evolved," Mr Rytenskild said.

Meanwhile, the industry has been tarnished by the revelations of animal abuse, including the ABC's footage of racehorses being sent to a slaughterhouse, and Melbourne Cup-winning trainer Darren Weir facing animal cruelty charges over the alleged torture, abuse and over-working of horses.

Mr Evans said there would be some people who would decide not to place a bet on the Cup this year because of those scandals but the full impact would be hard to quantify.

“There will be a proportion of the population who will be more reticent in placing a bet now than they would have been before - I don't think we can deny that," Mr Evans said.