Yokohama threw its hat into the ring on Thursday as a candidate to host a casino resort, a newly legalized segment of the tourism sector that the government hopes will stimulate the economy.

Yokohama joins the city and prefecture of Osaka, as well as Nagasaki and Wakayama prefectures, in vying to host so-called integrated resorts that are expected to attract more tourists and investment.

"We must look to Yokohama's future, the 20 to 30 years ahead," Mayor Fumiko Hayashi told a news conference, announcing its preparation of an official bid. "I've come to the conclusion that in order to achieve growth and development, we need IR."

Yokohama aims to open the resort at Yamashita Wharf, adjacent to popular sightseeing spot Yamashita Park, in the latter half of the 2020s, city officials said.

Japan is widely seen as a prize market for casino operators due to its affluent population of 128 million and proximity to Asia's wealthy gamblers. The government is expected to initially allow casino resorts at three sites.

Lawmakers finished legalizing casinos last year after a series of controversial bills and years of debate, with opponents citing risks of increased gambling addiction and organized crime activity.

Prolonged discussions meant no resorts will be open in time for the Tokyo 2020 Olympics.

But new casino resorts are expected to help Japan maintain growth in tourism and investment after the Summer Games are over. Some analysts have said the casino market could be worth around $20 billion (¥2.13 trillion) a year, or even more if resorts are opened in three cities.

International gaming companies, including Wynn Resorts Ltd., MGM Resorts International and Caesars Entertainment Corp., are eyeing the market, and may have to battle to win operating rights.