Customers of online betting exchange Betfair have punted an average $28.1 million a match on Cricket Australia's Big Bash League so far this summer.

On the first 23 games of the BBL 2013-14 season, the league's third since starting in 2011-12, Betfair customers lodged $590.6 million in bets.

In contrast, Betfair customers punted just under $6 million on 2013's Melbourne Cup.

Betfair spokesman Daniel Bevan said the extraordinary amount was due to Australian and international customers making ''in play'' bets, which allow punters to pick a winner after a match has begun. Appetite for betting during the match was heightened because competition in the BBL was fierce, he said.

''For Betfair customers, it is the evenness and the intrigue of every contest,'' Mr Bevan said.

''Momentum can shift so quickly, so it's encouraging people to stay and watch to the end. You almost have to stay and watch till the last ball each night.

''People can bet right up until the last ball and they do when it's so close.''

The match between the Hobart Hurricanes and Perth Scorchers was the most successful for Betfair so far this season, with $47.6 million bet on the game.

In Australia, it is illegal to make ''in play'' bets on internet sites, but local customers can use Betfair's telephone betting service.

Betfair is a betting exchange, rather than a wagering operator, which means bets made by customers have to be matched by other punters taking the opposite view of which team will win. As such, Betfair's turnover figures are a sum of both sides of a wager. Betfair takes a commission on winning bets.

Mr Bevan dismissed claims that large amounts bet on the games enhanced the risk of corruption.

''We're giving [Cricket Australia] another weapon for integrity and transparency because they have access to every trade for Australian and international punters,'' he said. ''Through onshore regulated operators like Betfair, those of us who play by the rules, we're delivering a financial return to Cricket Australia.''

As well as lining the coffers of gambling groups, Big Bash's abridged Twenty20 match format has been welcomed by viewers of beleaguered television channel Ten Network, which purchased the broadcast rights for five years for $100 million in June 2013.

The first 16 matches of the BBL, which are shown in prime time every evening, have attracted an average total of 629,000 viewers in the five major metropolitan markets.