MANILA - A typhoon that weather forecasters say may intensify as it nears land is bearing down on venues being used for the 30th Southeast Asia Games, adding to the woes that have bedevilled organisers since last week.

Typhoon Kammuri is expected to hit as early as Saturday evening (Nov 30), as the opening ceremonies for the Games are being held.

Kammuri, which means "crown" in Japan, is packing maximum winds of 139 kmh and gusts of up to 160 kmh, according to the latest bulletin from the US Navy and Air Force's Joint Typhoon Warning Centre.

"We're not ruling out the possibility that it may become a supertyphoon," Mr Chris Perez, a senior weather forecaster at the state-run meteorological agency here, said at a news briefing on Friday (Nov 29).

Kammuri is forecast to hit land on Tuesday (Dec 3) and cut a path across the main island of Luzon, dumping heavy rain on venues that will host 56 SEA Games events, before exiting the Philippines on Wednesday (Dec 4).

The biennial event will run till Dec 11.

Many venues are indoor. But the newly built track-and-field stadium in New Clark City, an economic zone 100km north of Manila, does not have a retractable roof. The "aquatic centre" at the same location, where all swimming and diving events will be held, is exposed on three sides.

The football matches in Manila, and outdoor events in Subic, a former US naval base near Clark, may also be affected. These include sailing, canoe and kayak races, beach volleyball and the modern pentathlon.

There are also obstacle course races and cycling events scheduled on Wednesday (Dec 4) south of Manila.

Mr Perez said the government was looking at raising the highest typhoon warning.

He said disaster-prevention officials should prepare for a storm as destructive as those that slammed the Philippines in 2014 and 2006, which had the same profile and hit at around the same time of the year.

The 2014 typhoon left over 100 dead, while the one that struck in 2006 killed over 730.

Kammuri will be the 20th typhoon to slam into the Philippines this year. The country is hit by an average of 20 typhoons each year, and the most destructive ones tend to come from October.

Typhoon season used to end in October but has stretched to December since the year 2000, a phenomenon experts blamed on climate change.

In November 2013, history's most powerful typhoon, barrelled across central Philippines. Haiyan levelled an entire city to the ground, left over 6,300 dead and displaced some 4 million.

The Philippine Southeast Asia Games Organising Committee (Phisgoc) said on Thursday (Nov 28) that it was readying contingency plans.

"We are prepared for that… There are sports where rains don't matter, but we will make contingency plans just in case the weather gets worse," Phisgoc executive director Tom Carrasco told reporters.

He said Phisgoc has been consulting with the chef de missions of the participating countries to reset some events. But he said the Games will not be extended.

"We have breaks or rest days that we can use. But definitely, the Games won't go beyond Dec 11," he said.

Singapore's chef de mission Juliana Seow said the city state's teams already in the Philippines had already been briefed on "the safety precautions to take".

"We are monitoring the situation, and our contingency plans will get underway in the event of severe weather conditions," she said in a statement.

Ms Seow said the teams were on standby in case their flights would have to be rescheduled.

"Our contingent's safety is the top priority while we minimise inconvenience for athletes who are preparing for their competitions during this period," she said.

Malaysia's chef-de-mission Datuk Megat Zulkarnain Omardin told The Star Online he was told "the typhoon would not hit hard, and it will only pass specified areas".

"But I do pray and hope that the situation will not be bad," he said.

The build-up to the Philippines hosting of the SEA Games has been mired in controversy, over allegations of spending irregularities, unfinished venues and poor treatment of athletes.

Social media has been abuzz with images of visiting athletes sleeping on the floor or on airport benches, transport hiccups and handwritten fixture lists, not enough drinking water and food unfit for athletes.

These have "displeased" President Rodrigo Duterte, who wants an investigation once the games are over.

Phisgoc chair Alan Peter Cayetano, Mr Duterte's running mate in the 2016 elections, has apologised for the "inconveniences" but downplayed the media's portrayal of the preparations as chaotic.