Some 50,000 people were in evacuation centres in the Philippines on Friday after fleeing their homes following days of torrential rains caused by Tropical Storm Meari, officials said.

More than 3,200 people fled their homes overnight in the capital Manila alone as the storm added to seasonal monsoon rains, bringing massive flooding to city streets, the civil defence agency said.

The swift evacuation of Manila residents as the waters rose overnight prevented any deaths, said Benito Ramos, executive director of the official National Disaster Risk Reduction and Management Council.

"It is a good thing we pre-positioned rubber boats. Thankfully, people reacted well. When we told them to evacuate, they evacuated," Ramos said.

However 11 people were still missing in or near the less-developed Bicol peninsula southeast of Manila that bore the brunt of Meari as it brushed past the eastern side of this country, the council added.

The missing included 10 fishermen who ventured out to sea from the island of Catanduanes before Meari struck and a woman swept away by flash flooding in another part of Bicol, a council said.

The rains, which have been falling for most of the week, intensified on Thursday, forcing people to flee their homes, fearing floods and landslides.

Most schools in and around Manila cancelled classes on Friday due to the flooding with debris blocking many streets, authorities said.

Science Department Undersecretary Graciano Yumul said that rain would further intensify over the main island of Luzon where Manila is located, even though the storm was moving away from the Philippines towards Taiwan.

The government weather station reported that Meari had strengthened as it moved northwest towards Taiwan, with gusts of 100 kilometres (60 miles) per hour.