Just a month ago, the Diet session opening Monday was expected to hotly debate but ultimately approve more specific measures on how Japan will operate what will eventually be its first casino resorts.

But following a casino-related bribery scandal that erupted in December, Prime Minister Shinzo Abe's government finds itself facing increased public calls to reconsider and tougher political opposition toward their authorization, both of which could mean further delays before their eventual debut.

The scandal erupted when Liberal Democratic Party lawmaker Tsukasa Akimoto was questioned and subsequently arrested on Christmas Day for allegedly accepting ¥3 million in cash in 2017 and about ¥760,000 for a trip to Hokkaido in 2018 from the Chinese company 500.com.