Gambling by mobile phone is on the rise worldwide and the biggest growth in the industry is expected to take place in Asia. But, an unclear legal situation in most of the region could slow the market's growth.

Governments from Singapore to South Korea are increasingly lifting restrictions on gambling. But gamblers do not have to wait for new casinos to open to place their bets: They can just use their mobile phones.

Walter Adamson, an Australian consultant for Internet and mobile services, says the requirement for what is called mobile gambling is a phone that can connect to the Internet, where gaming operators offer special sites.

"The provider of your system needs to provide a mobile Internet service and many telephone companies, particularly in Japan, [South] Korea and increasingly in China, provide Internet services on the mobile phone," said Walter Adamson. "Then they can access any Internet site that is designed for access by mobile phones."

Europe is the largest market for mobile gambling, but telecommunications analysts predict that Asia will catch up soon.

British Informa, a telecom and media consulting company, forecasts that close to 100 million people in the Asia-Pacific region will use mobile phones to place bets in 2010, half of the users globally.

The mobile gambling market in Asia is just starting to take off. Its growth is still limited by the lack of suitable phones. Another obstacle for gaming operators is the unclear legal situation in many places.

Legal gambling by phone is so far restricted to only a few countries. In Hong Kong, gamblers can use mobile phones to bet on horses and football through the city's Jockey Club, and China authorizes lotteries via mobile phone. But remote casino-style gambling is only allowed in the Philippines and Macau. In most of the region, mobile gambling remains a gray area in terms of government regulations.

But Yap Wai Ming, director of the Stamford Law Corporation in Singapore, says even in those places gambling by phone is already available.

"Legally it is not possible but practically speaking people are already offering it," said Yap Wai Ming. "I give you an example, the casino. There are a lot of Internet casinos that are not regulated but people are still playing on it and money is still being exchanged. Only if they are caught they will be punished."

Gambling has long been a passion in much of Asia, with legal and illegal operators running lotteries, horse races, cockfights and other betting games. Some countries have expanded legal gambling in recent years, including Hong Kong, which has legalized soccer betting, and Singapore, which plans to allow its first casino to open in a few years.

Many governments are cautious about legalizing mobile betting, because it draws money away from legal domestic operators, which pay taxes, or because of social concerns about the dangers of gambling.

Gambling operators hope that regulatory and technical challenges will be resolved in the next few years, because the mobile gambling market is lucrative. The Asia-Pacific region is forecast to generate revenue of nearly $3 billion in 2010.