Manila - Toxic pesticides inside a sunken Philippine ferry have so far not contaminated surrounding waters, but foreign experts urged the government to intensify monitoring to prevent an environmental disaster, officials said Friday.

A joint team of the European Union and the United Nations visited the capsized MV Princess of the Stars off Sibuyan Island, 300 kilometres south of Manila, earlier in the week to examine possible contamination of the waters.

More than 800 people are dead or missing from the accident, which occurred at the height of powerful typhoon Fengshen that pummeled the Philippines last month.

Transportation Undersecretary Elena Bautista said the vessel was carrying 10 tons of endosulfan, a toxic pesticide, at least 250,000 litres of bunker fuel, and other pesticides that can be potentially harmful to the environment and to humans.

"The experts noted no observable oil sheen or environmental pollution or fish kills within the vicinity of the shipwreck," she said. "They reported the efforts of government so far have been successful in preventing and controlling an environmental and human disaster."

Ambassador Alistair MacDonald, head of the EU Delegation to the Philippines, said the experts recommended more intensive monitoring with "special attention to actions that may need to be taken in case of acute situations, such as a further typhoon in the area."

"The team said that while there is no visible oil monitored and no monitored endosulfan on site, the fishing ban represents a prudent precaution in this situation," he said.

Bautista expressed hope that salvage operations to re-float the sunken ferry could finally commence in the first week of August. The ship's owner, Sulpicio Lines, has yet to contract a salvage firm to do the work.

The sinking of the Princess of the Stars was one of the worst ferry disasters in the Philippines, the site of the world's worst peacetime shipping accident when a passenger ferry collided with an oil tanker in 1987, killing more than 4,000 people. dpa