MACAU, China – In years past, Raymond Wong laid his chips on the worn-out felt of the baccarat tables at the Lisboa casino, a windowless space that epitomized the seedy reputation of this gambling enclave in southern China. Cigarette smoke hovered over throngs jostling for spots at the tables. Prostitutes trawled the hallways.

But on a recent evening, Mr.Wong instead went to the glass-fronted Sands Macao casino, a landmark property erected by the Las Vegas Sands Corporation, best known for its Venetian hotel in Nevada. With its seven restaurants, live cabaret acts, and private club complete with wine cellar and spa, the $265 million Sands has become an emblem for this Asian gambling haven, which is pursuing an aggressive transformation to capitalize on the growing affluence of China.

“The air is better, and the furnishings are all new,” Mr. Wong, who is 55 and rides the ferry from Hong Kong once or twice a month, said. “This is something fresh.”

Enticed by growing numbers of visitors from China, the world’s most populous country, the same companies that erected many of Las Vegas’ more prominent resort casinos are investing billions of dollars in this former Portuguese colony. They are bidding to turn Macau from a place synonymous with prostitution, money laundering, and binge gambling into what some are billing Asia’s Las Vegas – a hive of trade shows, restaurants, shopping and entertainment, in which gambling is but one piece of a glitzy resort experience for the masses.

“What we did was simply build the antithesis of what was here already,” said Frank McFadden, chief operating officer of Venetian Macao, which operates the Sands, as he sat in a velvet lounge chair in the cigar room of the members-only Paiza Club. “It’s a proven experience that works, and it’s just being put into a pure virgin market.”

Already, though, the market is huge. Macau’s gambling revenue nearly tripled to $5.8 billion last year from $2 billion in 2000, according to the local government, pulling nearly even with the world’s most lucrative gambling center, the Las Vegas Strip, which last year took in $6 billion, according to the Nevada Gaming Control Board.

The gambling boom has enticed Singapore to pursue its own casino plans, with major companies flocking to that island nation as well in pursuit of largescale projects.

“The proclivity of Asian people to gamble is pretty staggering,” said Terry Lanni, chief executive of MGM Mirage, whose $1.1 billion, 600-room MGM Grand Macao is slated to open late in 2007. “People borrow from loan sharks and gamble with it.”

Here in Macau, the outside investors are betting they can carve into the empire of Stanley Ho, the 84-year-old magnate who enjoyed a gambling monopoly here for four decades, before Macau’s government opened the door to foreign firms in 2001. Mr. Ho and his family still operate 15 of Macau’s 18 casinos.

Across the street from Mr. Ho’s Lisboa – still the top-grossing property in town – Wynn Resorts, led by Las Vegas icon Stephen Wynn, is erecting a $1.2 billion, 600-room hotel and casino slated to open in early September. It will include 200 gambling tables, 340 slot machines, a ballroom seating 700, and 28,000 square feet of retail space.

“There’s a huge untapped market,” the president of Wynn Resorts in Macao, Grant Bowie, said. “We’ve just got to build a destination.”

To the south, on 500 acres of reclaimed land between the islands of Coloane and Taipa,Sands is making the biggest bet of all – a $4.5 billion complex of casino resorts and meeting space known as the Cotai Strip. It is anchored by the 3,000-room, all-suite Macau Venetian Casino Resort – a copy of the Las Vegas property, with faux canals and gondoliers – including a 2,000-seat theater, 850,000 square-feet of retail, and a 1.4 million-square foot exhibition center.

The first phase alone will add 12,000 hotel rooms by 2009, more than doubling all of Macau’s hotel capacity. Some 3,000 workers, 30 cranes, and 50-plus dump trucks are erecting the new Venetian, slated to open the middle of next year. A six-star, 400-room Four Seasons hotel is going up alongside. The Shangri-La chain has pledged to build two hotels on the strip.

Underlying these investments is the rise of the Chinese leisure class. Macau sits on the doorstep of mainland China. Three years ago, as outbreaks of severe acute respiratory syndrome, or SARS, decimated tourism in Hong Kong and Macau, the Chinese government eased travel restrictions, freeing people to visit independently. The number of visitors to Macau rose from 11.9 million in 2003 to 18.7 million last year. About 30,000 people waited in line to visit the Sands on opening day two years ago. During the recent Chinese New Year holiday, roughly 69,000 people passed through the doors.

Where visitors to Las Vegas stay an average of more than three days, most people who come here don’t even spend the night, returning to Hong Kong by ferry or by road to the cities of the southern Chinese province of Guangdong.The projects underway are aimed at keeping them here.

Already, though, some are warning that a gold rush mentality is erecting more resorts than even China can fill. Macau had 1,388 gambling tables at the end of last year but is on track to have more than 4,000 by 2009, an analyst at South China Research in Hong Kong, Andes Cheng, said. After surging by more than 40% in 2004, gaming revenue grew by only about 10% last year, according to local government figures.

“It’s a bubble,” Mr. Cheng said. “There will be lots of supply.”

The foreign investors acknowledge this but say that they will be the ones positioned to capture new customers, while older, poorly maintained properties disappear.