The Foreign Ministry did not elaborate on those measures in a statement that called Manila the "real regional trouble maker" for reinforcing the ship, which has sat on Second Thomas Shoal since 1999. The wording of the warning mirrors what China has said in the past when it's particularly angry with other countries.
Reuters reported on Tuesday that the Philippine navy had been using wooden fishing boats and other small craft to move cement, steel and welding equipment to the BRP Sierra Madre since late last year for repair work aimed at stopping the ship from breaking apart.
Manila regards Second Thomas Shoal, which lies 105 nautical miles (195 km) southwest of the Philippine region of Palawan, as being within its 200-nautical mile exclusive economic zone. China, which claims virtually all the South China Sea, says the reef is part of its territory.
The 100 meter-long (330-foot) BRP Sierra Madre, a tank landing ship, was built for the U.S. Navy during World War Two.
It was eventually transferred to the Philippine navy, which deliberately grounded it on Second Thomas Shoal to mark Manila's claim to the reef in the Spratly archipelago of the South China Sea. A small contingent of Philippine soldiers are stationed onboard.
China's Foreign Ministry said it was "extremely dissatisfied with and resolutely opposed to" the repairs.
Manila had promised many times to remove the ship, but the repair work showed it was "two faced", it said.
"China's determination to maintain its national territorial sovereignty and maritime rights is resolute. China again urges the Philippines to immediately stop its illegal encroachments and fulfill its promises to remove the ship," the ministry added.
In a statement issued after the Reuters report, Colonel Edgard Arevalo, the spokesman for the Philippine navy, said "minor repairs" were being done to the vessel.
"It behoves the Philippine navy to ensure the ship's habitability and safety," Arevalo said.
Just to the west of Second Thomas Shoal is Mischief Reef, one of seven coral formations in the Spratlys that China is rapidly turning into islands that Beijing says will have undefined military purposes.
