* MGM prepared to invest up to 1 trln yen

* Investment likely via real estate investment trust

* Company could invest up to 300 bln yen on regional facility

* Odds for legalisation of casinos have improved

By Thomas Wilson and Emi Emoto

TOKYO, Oct 31 (Reuters) - Las Vegas-based MGM Resorts International could plough almost $10 billion into a Japanese casino via a publicly traded real estate investment trust, its chief executive said on Monday, as Tokyo inches closer to legalising the industry.

Casinos are currently banned in Japan, but the odds of their legalisation have improved sharply thanks to political shifts that could open the world’s next great frontier for high-roller gambling.

Chief Executive Officer James Murren said MGM would spend between 500 billion yen and one trillion yen ($4.8 billion-$9.5 billion) on an “integrated resort” - a large-scale project combining casinos with hotels, shopping and conference space - in Tokyo, Yokohama or Osaka.

Multiple blue-chip companies would look for an equity stake in an MGM-led project, he said, suggesting high hopes for a Japanese gaming market that brokerage CLSA says could be worth $40 billion annually.

“We think there would be a tremendous amount of demand, and ultimately a public listing of these types of Japanese resorts would be very appealing,” Murren told Reuters in an interview.

Rival operators keen to enter the market include Las Vegas Sands Corp, which said in 2014 it would invest up to $10 billion in Japan.

If a law laying the framework for legalised casinos passes the Japanese parliament, fresh legislation would set out details such as the location of the casinos.

MGM could spend 100 billion yen to 300 billion yen on a resort in a regional area, Murren said, possibly Hokkaido in northern Japan or the southernmost main island of Kyushu, although it was mainly interested in a metro area.

The company has previously flagged its desire to invest in a Japanese resort but it has not disclosed details of how it would do so.

Murren said he envisaged a REIT where an MGM-controlled operating company responsible for expenses and investment would pay rent to a property company owned by private investors and domestic and foreign companies.

“That could be an interesting way to expand the level of involvement, as there are many investors who are risk averse and looking for yield and others who are more risk tolerant,” he said.

A resort in Tokyo, Osaka or Yokohama could be built by 2022-23, Murren said, speaking to Reuters after a closed-door discussion with Japanese and international businesses on casino resorts.

Beverage maker Suntory Holdings Ltd Chief Executive Takeshi Niinami and ruling Liberal Democratic Party lawmaker Takeshi Iwaya, both prominent casino backers, also spoke at the discussion, people familiar with the matter said.

Suntory Holdings did not immediately respond to requests to confirm Niinami’s attendance.

In April, MGM launched in the U.S. a publicly traded REIT consisting of 10 of its U.S. properties, MGM Growth Properties LLC. ($1 = 104.8500 yen) (Reporting by Thomas Wilson; Editing by Stephen Coates)