The Bangkok skyline, seen from the Rama III bridge. Yet another casino study predicts a legal casino would boost tourist arrivals by 50% over today's 25 million. (Photo by Seksan Rojjanametakul)

More than 100 billion baht a year in tax revenue is expected to pour into state coffers if casinos are legalised in Thailand, according to a study conducted by the dean of Rangsit University's College of Social Innovation.

The estimated revenue excludes contributions from tourism and conferences, Sungsidh Piriyarangsan said.

He said it took three years for the Singaporean government to see annual tax revenue from legal casinos reach the 100-billion-baht threshold, but Thailand should take less time since the country had plenty of tourist attractions.

The idea of legal casinos was floated by former national police chief Somyot Poompunmuang last year.

However, the proposal lost steam after Prime Minister Prayut Chan-o-cha put the brakes on the idea.

The call for legal casinos is nothing new, as the idea was raised by previous governments but went down to strong public criticism.

The idea came up under the Thaksin Shinawatra government in 2004, the Samak Sundaravej government in 2008 and the Yingluck Shinawatra government in 2011.

Mr Sungsidh said casinos could be legalised only after winning widespread public support and with the backing of an honest government and operators interested in running the business.

An increasing number of middle-income earners agree with the concept of legal casinos in Thailand, he said.

He reiterated that the Prayut government had shown no support for the idea.

To alleviate the negative impact from legal casinos, Singapore's laws governing the business are a good example for Thailand to follow, he said.

The Singaporean government permits only those aged 21 or older to enter and place bets at legal casinos.

Anyone deemed to have a gambling problem can be barred from entering.

Mr Sungsidh said legal casinos would also boost the number of foreign tourists visiting the country by 40-50%, based on the models of Singapore and Macau.

Legalisation would also reduce the number of criminal cases, he said.

The study found Sa Kaeo province on the Cambodian border had a lower number of criminal cases, as the legal casinos in Cambodia helped to create jobs and boost incomes.

At present, Thailand and Brunei are the only two Asean members without legal casinos, Mr Sungsidh said.

Neighbouring countries are home to at least 120 legal casinos, mostly in Cambodia and Laos.

Macau is seen as a model for boosting tourism through casino gambling. Rangsit University's Sungsidh Piriyarangsan says Thailand could see a rise in foreign visitors of up to 50%. (Photo by Pichaya Svasti)

Mr Sungsidh's team surveyed 2,500 Thais during May to August last year.

Most respondents agreed with the idea of a legal casino-resort complex, saying it would create jobs and boost tourism revenue.

In addition, Thai casinos would keep local gamblers from visiting casinos abroad.

But the survey also uncovered concerns about crime fostered by casino culture and violations of religious principles and ethics.

Mr Sungsidh suggested if the government decided to legalise casinos, it must use the revenue generated from the business to help society.

It must also allow people to examine the source of revenue in a transparent manner, he added.