MANILA, Philippines -- Muntinlupa City Mayor Aldrin San Pedro appealed on Wednesday to the Department of Public Works and Highways (DPWH) to open the Napindan floodgates to allow water from the swollen Laguna Lake to enter Pasig River.

According to San Pedro, eight of the city's nine villages are still under two-meter high floodwaters since storm "Ondoy" battered Metro Manila on Saturday.

He said the floods in Muntinlupa and other lakeshore communities around the Laguna Lake were triggered by the swelling up of the lake after the storm dumped an unusual amount of rainwater in the eastern part of the metropolis.

The floods, he said, have not receded because the natural path of the water from the lake was being blocked by the Napindan floodgates.

San Pedro surmised that the DPWH denied his request to open the floodgates to prevent floodwaters from reaching Malacañang at a low-lying portion of Pasig River.

"If that is the case, then perhaps the DPWH should just calibrate the amount of water that the floodgates would take in," the mayor said in a press briefing.

San Pedro also asked the DPWH and the Department of Environment and Natural Resources to immediately start the dredging of a silted waterway in Taguig-Pateros area to allow water from the lake to flow into Pasig River.

He said at least 3,000 families composed of over 15,000 individuals were still camped in eight evacuation centers in the city and the homes of 40,000 families were still flooded as of Wednesday.

Some of the areas where the residents sought refuge have been swamped by waist-deep floodwaters, he added.

The mayor feared of an outbreak of mosquito-borne diseases like dengue and other illnesses in overcrowded evacuation centers.

He noted that in the Alabang Elementary School, only one portable toilet was available to nearly 4,000 evacuees.