* Year-on-year growth was 12.3 pct, analysts expected 15-17 pct rise
* Revenue figure second weakest this year
* Visitor levels have continued to fall
By Farah Master
HONG KONG, Oct 4 (Reuters) - Gambling revenue in Macau rose a weaker-than-expected 12.3 percent in September, indicating China's slowing economy is increasingly hurting the appetite of wealthy mainland gamblers to place bets in the world's largest casino market.
September's revenue at 23.87 billion patacas ($2.99 billion), announced by the Macau government on Thursday, was the second weakest revenue figure this year.
Analysts had forecast September growth in the tiny enclave on China's southern coast, to be up 15-17 percent, ahead of a national holiday week starting on October 1.
The Chinese economy's slowdown and increased political scrutiny due to an impending leadership change have taken their toll on the mainland's big-spending billionaire punters, pushing Macau's gambling revenue growth levels down substantially over the past five months.
The former Portuguese colony, which is reachable from Hong Kong by ferry in an hour, is the only place where the Chinese can legally gamble at casinos in the country.
Macau's economy, one of the world's fastest growing last year, relies heavily on the gambling industry. The sector contributes around 40 percent of the casino-crammed hub's GDP.
Visitor levels have continued to trend downwards, with August registering 0.6 lower visitation year-on-year, adding to the competitive pressure amongst the six casino players operating in Macau, including Las Vegas stalwarts Steve Wynn, through his Wynn Macau unit, and MGM China .
Sands China , controlled by casino magnate and high-profile Republican donor Sheldon Adelson, opened a new resort in Macau, adding a new casino and a Sheraton hotel to Macau's expanding casino skyline.
September's weaker number was due in part to a slowdown in revenues in the last week, ahead of the long October holiday as the first three weeks were relatively strong, analysts said. They expected October data to show a bounce back.
Shares of Macau gambling companies fell 3-4 percent in Hong Kong on Thursday after the September data was released compared with a 0.1 percent gain on the main Hong Kong index .
"There could be some profit-taking in the short term unless there is anything positive happening on the policy side," Victor Yip, analyst at brokerage UOB Kay Hian in Hong Kong, said about the share moves.
(Editing by Muralikumar Anantharaman)
Keywords: MACAU REVENUES/