MANILA, March 19 (Reuters) - Foreign and domestic firms are expected to invest much as $6 billion in the Philippines' casino sector in the next five years, the head of its gaming regulator said, bolstering its status among Asia's top gambling destinations as competition increases.

At least one new casino-resort will open every other year including in areas outside Manila like Clark, a former U.S. military base north of the capital, and Cebu in the country's central region, Philippine Amusement and Gaming Corp Chairman Alejandro Tengco said on Tuesday.

"We will have continued growth because of the opening of new casinos and the expansion in the electronic gaming segment," Tengco told Reuters at the sidelines of the ASEAN Gaming Summit.

Tengco said the Philippines would likely hit its target of 450 billion to 500 billion pesos ($8-9 billion) in total gross gaming revenue (GGR) by 2027, a year earlier than expected.

In 2023, the Philippines posted a record 285 billion pesos in total GGR, a key industry metric representing the amount players wager minus their winnings, government data showed.

Gamblers from Japan, South Korea and Singapore, and domestic mass market players took up the slack from the absence of mainland Chinese high-rollers after the pandemic and tightening of rules on junkets.

That allowed casino resort operators like Bloomberry Resorts and Japan's Universal Entertainment, and units of Philippine conglomerates SM Investments and Alliance Global Group to post strong performances last year, Tengco said.

The Philippines' freewheeling gaming industry is bracing for regional competition from Japan, which has approved its first casino, and Thailand, which is again considering legalising casinos.

"We have about five to six years to fortify and solidify so when they open, we are mature already," Tengco said. ($1 = 55.70 Philippine pesos) (Reporting by Neil Jerome Morales; Editing by Jamie Freed)