Shares of Macau casino operators slumped on Monday on worries of weakening demand from wealthy Chinese consumers, the main players in the world's largest gambling market, leading investors to sell stocks that have hit record highs in the past few months.

Shares in the six casinos fell between 6-13 percent during the session, with Galaxy Entertainment the biggest loser, falling 11.4 percent by 0700 GMT. MGM China slid 9.8 percent while Wynn Macau dropped 10.4 percent.

By comparison, the benchmark Hang Seng Index was down 0.4 percent.

A key reason for the sector slump, which also saw Macau kingpin Stanley Ho's SJM drop 6.7 percent, Sands China 8.6 percent and Melco International Development 9.5 percent lower, was concern that gaming revenue growth would begin to recede towards the end of this year.

Valuations for the billion dollar firms have risen as Macau posted record beating revenue figures since the start of the year, with investors betting on sustained stellar growth in the former Portuguese enclave.

Gaming stocks have outperformed relative to other sectors year to date and therefore the sector could be very attractive for shorting and for people to take profit, said Victor Yip, analyst at UOB Kay Hian in Hong Kong.

Gaming Stocks still could have a little more downside, he added, but said gaming revenue for the next few months was likely to remain robust due to mainlanders spending their holidays in the glitzy enclave.

Deutsche Bank analyst Karen Tang wrote in a note that Macau's growth may disappoint the market after October's national Golden Week, with Chinese consumer spending slowing.

We forecast that gaming revenue growth may fall down significantly to 34 percent year on year in October, then 32 percent year on year in November, and then to 20 percent year on year in December, she wrote, citing that high rolling VIP gaming revenue, which contributes to over 70 percent of gaming revenues, will have no further liquidity boost from operators.

Mass gaming revenue will also be affected by a shift in seasonal travel, she wrote.