Japan's opposition launched a last-ditch bid Wednesday to stall passage of a controversial bill to legalise casinos.

But the censure motion against Prime Minister Shinzo Abe was expected to be voted down by his ruling coalition, local media said. 

The move is among several motions designed to hold up passage of a bill that would open up a market seen as a potential global gaming powerhouse rivalling Asian titan Macau.

The long-awaited legislation is still expected to be passed by parliament, possibly late Wednesday evening.

It comes after years of delays and political wrangling linked to worries about gambling addiction and organised crime. A 2013 push to pass the bill was abandoned in the face of strong opposition.

The ruling Liberal Democratic Party (LDP) and its junior partners are reportedly considering extending the current parliamentary session, which ends on Wednesday, to ensure the bill is passed by the end of this year.

More legislation outlining details of integrated resorts -- which will feature hotel, retail, convention centre and entertainment options including betting parlours -- is required before casinos can actually be built.

That makes it unlikely Japan will have any operating casinos before Tokyo hosts the 2020 Olympics.

But Abe and his party are betting that casinos will support tourism after the games, and pump some life into the world's number three economy.

Supporters have said casinos could bring huge investment to the once-booming economy and pose a challenge to Macau, with some analysts envisaging a $30 billion market.

Japan has long been viewed as a massive gaming market due to its wealthy population, close proximity to China and appetite for other forms of legal gambling, including horse and boat racing.

Pachinko, a slot machine-style game played in thousands of smoky parlours in every corner of Japan, is a huge revenue generator. Winnings can be exchanged off-site for cash, skirting gaming laws.

But casinos do not have wide public support, largely due to concerns about addiction and crime.

Japan's public broadcaster NHK released a survey this week that showed just 12 percent of respondents favoured scrapping the current ban on casinos, while 44 percent were opposed and the rest uncertain.