State-owned PTT's retail unit, PTT Oil and Retail (PTTOR), which owns coffee shops and gas stations, is preparing for the float, PTTOR CEO Jiraphon Kawswat said at a news conference.

"The filing is in process and there are procedures we have to follow because there are many parties involved," Jiraphon said without giving further details.

PTT's plans to take its retail flagship public comes at a time when firms in Thailand, as well as in the Philippines, are leading a revival in regional IPOs, spurred by growing investor interest in firms focused on Southeast Asian consumers.

Asset World Corp, the hospitality and property firm listed by Thai billionaire Charoen Sirivadhanabhakdi, and Philippine home furnishing retailer AllHome Corp have this year raised $1.6 billion and $285 million, respectively.

On Monday, Thailand's largest industrial conglomerate, Siam Cement Group Pcl, announced plans to list its packaging unit, SCG Packaging, in what sources say could raise up to $1 billion.

Top Thai retailer Central Group, owned by the billionaire Chirathivat family, has also filed for the IPO Central Retail Corp, combining retail businesses in Thailand, Vietnam and Italy. Refinitiv IFR has pegged the IPO size at between $1 billion and $2 billion.

PTT Oil and Retail, best-known for its Cafe Amazon coffee chain which has 2,800 stores across the country and 200 branches in Singapore, China and Oman, plans to expand its non-oil business, CEO Jiraphon said. "The proportion of profit from the non-oil business will increase."

PTTOR has 1,850 gas stations in Thailand and 280 gas stations throughout the region in Laos, Cambodia and the Philippines.

"We also plan to grow inorganically through investments in new businesses and joint ventures in Thailand and overseas," Jiraphon said.

(Reporting by Chayut Setboonsarng; Editing by Himani Sarkar)