In separate writs filed in Hong Kong's High Court this week, the casino is seeking to recover HK$23 million from Shanghai businesswoman Zou Yunyu and more than HK$11 million from Xie Xiaoqing, a delegate to the National People's Congress.

The casino said they each borrowed money in the form of gaming chips.

VIP Chinese gamblers flock to Macau as it is the only place in China where citizens can legally gamble in casinos, boosting the gaming revenues of the former Portuguese colony. But casinos there run the risk of not being able to recover any debts once gamblers return to the mainland because such debts are not recognized by Chinese courts.

The lawsuit filed by the Venetian Macau is atypical in that most casinos prefer to rely on junket operators - agents who find and ferry around high-rollers and arrange credit - to collect debts rather than go through the courts.

The credit agreements for Zou and Xie set an 18 percent annual interest rate on outstanding debt, according to the writs.

Neither of the defendants was immediately available to comment.

Zou was ranked 302nd out of 400 richest Chinese by Forbes magazine in 2008 with a fortune of 1.5 billion yuan ($241.23 million).

Adelson's Venetian Macau, a unit of Hong Kong-listed Sands China, is a massive casino resort on reclaimed former swampland that is now home to five-star hotels and designer shops with some of the highest sales in the world.

Macau, a cash cow for local billionaires and U.S. tycoons such as Steve Wynn and Adelson, raked in $38 billion in annual gaming revenues in 2012.

China has been pressing Macau to step up scrutiny of money transfers as part of a broader move to combat corruption and promote "responsible gaming" in the casino halls of the world's largest gambling hub.

China imposes strict limits on how much money - $50,000 - its citizens can take out of the country, making Macau a valve for hot money escaping the world's second-largest economy. ($1 = 7.7532 Hong Kong dollars) ($1 = 6.2181 Chinese yuan)

(Editing by Anne Marie Roantree and Ryan Woo)

By Grace Li