Seventeen Hongkongers were arrested as police smashed an illegal gambling syndicate tied to money laundering through HK$240 million laid in bets.

Six suspects - five men and a woman - were identified as key members while eight men and three women were said to have been stooges to open and use accounts at local virtual banks in exchange for sums from HK$700 to several thousand as rewards.

The 17 are aged from 21 to 50.

Senior inspector Chan Lok-shun of the financial intelligence and investigation bureau said after opening accounts the stooges handed over bank cards and online banking information to core members.

The syndicate recruited punters via social media websites, claiming to be offering mahjong, poker and baccarat games online.

Punters were then provided with points to be used as bets.

The syndicate takes bets of up to tens of thousands of dollars per game.

To conceal the operation the syndicate rented a 1,000-square-foot flat in an industrial building in the New Territories as a money laundering office.

From there members made online transactions between banks.

"We believe the syndicate used at least 18 virtual bank accounts to launder some HK$240 million of criminal proceeds from June to April," Chan said.

In an operation codenamed Calmorder on Tuesday and Wednesday, the key members were arrested for conspiracy to commit money laundering. They included a couple and former schoolmates while the stooges included housewives.

Police found betting records on a bank of computers.

Officers also seized HK$760,000 in cash, 16 computers, 80 phones, 270 SIM cards and bank documents and ATM cards.

17 in betting ring busted