Thailand's prime minister cancelled plans to attend a Pacific trade forum in Hawaii this weekend as she struggled Tuesday to cope with her country's worst flooding in a half-century.

The flooding began in late July and has killed 527 people, mostly by drowning. Some provinces north of Bangkok have been inundated for more than a month, although floodwaters there have started to recede in recent days as massive pools of runoff flow south.

The water has inexorably made its way into Bangkok, causing distress among the capital's more than nine million inhabitants and heightening criticism of government's inefficiency in countering the problem.

"Now it's time for all Thai people to help each other, so I've informed (the host) that I would not go," Prime Minister Yingluck Shinawatra said.

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A Buddhist monk walks on a foot bridge while collecting alms at a flooded area in Bangkok on Tuesday. (Sukree Sukplang/Reuters)

The Asia Pacific Economic Cooperation summit, hosted by President Barack Obama, will bring together 21 leaders, including Chinese President Hu Jintao.

It would have given Yingluck an opportunity as a novice politician to gain diplomatic lustre, but also could have opened her to criticism of ignoring flooding at home where her political rivals are keen to exploit any problems due to the waters.

She had already cancelled a get-acquainted trip to China last month because of the flood crisis.

Team to co-ordinate water managment

Yingluck came to office in August after a Pheu Thai party landslide, but is widely seen as a stand-in for her brother, former Prime Minister Thaksin Shinawatra, who was ousted by a military coup in 2007 after being accused of corruption and abuse of power.

Yingluck on Tuesday announced a recovery plan including the creation of a team to co-ordinate water policy.

About a dozen separate agencies deal with different aspects of water management, with little consultation and no clear lines of authority, hindering both planning and response to crises.

Her government also reached out to Japanese businesses, who are major investors in the seven big industrial parks in and around Bangkok that have halted production because of the flooding. They had complained they were not properly informed of the threat of the floods.

Virabongse Ramangkura, who heads a new reconstruction committee, said he will consult in Tokyo with Japan's Ministry of Economy, Trade and Industry on how to aid the stricken businesses.

Japan's ambassador later Tuesday accompanied Yingluck for an inspection tour to Ayutthaya, where several of the industrial estates are located and cleanups have begun.

Evacuations in Bangkok

Energy Minister Pichai Naripthaphan said late Monday that Bangkok's flood crisis is likely to drag on for another month, though the water may finally begin to subside in the capital by mid-November.

Top officials and experts have given varying estimates of how much Bangkok would flood and how long the threat would loom over the city, with some claiming several weeks ago the biggest window of danger to the sprawling metropolis had already passed.

Instead, the flood threat has only intensified, straining sandbag-stacking residents as more and more neighbourhoods are swamped each day. The seemingly unstoppable floodwaters have overwhelmed canals, seeped up through drains and poured down condominium-lined highways. The water has now begun surrounding the city's northernmost subway stops, threatening to shut them down.

Evacuations have been ordered in 12 of Bangkok's 50 districts, with residents of the northern district of Klong Sam Wa told to leave Monday. The evacuations, which also affect parts of several other districts, are not mandatory, and many people are staying to protect homes and businesses.

On Tuesday, Football Federation Australia said a World Cup qualifier against Thailand scheduled for next week was moved to a smaller stadium in Bangkok because the original venue is being used as a flood evacuation centre.

Meanwhile, cleanups have begun in provinces to the north, including Nakorn Sawan and Ayutthaya, site of Thailand's ancient capital. The prime minister planned to visit Ayutthaya later Tuesday to witness recovery efforts.