More than 100 police have been deployed near the Chinese Consular
Office, said local media, ahead of a demonstration expected to draw
hundreds of people.
The two countries have been locked in a stand-off in disputed waters at the Scarborough Shoal since 8 April.
Both sides accuse each other of intruding into territorial waters.
The row began early last month when the Philippines said its
naval ship had found eight Chinese fishing vessels at the shoal, which
both sides claim.
A number of Chinese and Philippine fishery and coastguard
ships remain stationed at the shoal, with both sides refusing to
withdraw.
Tours suspended
Philippine officials said they expected the protest to be peaceful.
Protest organisers say demonstrations are planned at several Chinese diplomatic missions around the world.
In an advisory, the Chinese embassy in Manila advised its citizens to stay off the streets.
Chinese state media also reported on Thursday that most travel agencies had suspended tours to the Philippines.
An official at one agency confirmed the suspension to the BBC, while another said clients were being warned not to travel.
China has also warned the Philippines that it was prepared to respond to ''any escalation'' in the maritime situation.
State media has given the issue widespread coverage in recent
days, warning of damage to bilateral ties and vowing not to back down.
A Xinhua news agency commentary published late on Thursday
said Chinese people "were enraged by the offensive behaviour of the
Philippines" over the issue.
The shoal itself, called Huangyan Island by China, is a
series of rocks and reefs more than 100 miles (160km) from the
Philippines and 500 miles from China.
China claims sovereignty over a large U-shaped area of the
South China Sea, bringing it into dispute with several neighbouring
countries. In recent months it has grown more assertive over the issue.
Manila has asked China to settle the issue at the International Tribunal on the Law of the Sea (ITLOS).
Source: BBC News