MANILA, July 9 (Reuters) - The Philippines rejected on Tuesday China's accusation that its grounded warship on the contested Second Thomas Shoal in the South China had damaged the coral reef ecosystem in the area, laying the blame for damaging the marine environment on Beijing.

The Philippine task force on the South China Sea in a statement called for an independent, third party marine scientific assessment of the causes of coral reef damage in the South China Sea.

"It is China who has been found to have caused irreparable damage to corals. It is China that has caused untold damage to the maritime environment, and jeopardised the natural habitat and the livelihood of thousands of Filipino fisherfolk," the task force said.

On Monday, China's Ministry of Natural Resources said in a report that Philippine warships have been "illegally beached" around Second Thomas Shoal near what it calls Nansha Islands for a long time, "and it has seriously damaged the diversity, stability and sustainability of the reef ecosystem".

The Philippines and Beijing have been embroiled in confrontations at the Second Thomas Shoal where Manila maintains a rusting warship, BRP Sierra Madre, that it beached in 1999 to reinforce maritime claims. A small crew is stationed on it.

China has in turn dredged sand and coral to build artificial islands in the South China Sea, which it says is normal construction activity on its territory, but which other nations say is aimed at enforcing its claim to the waterway.

A report by the Center for Strategic and International Studies last year found China's construction activity buried more than 4,600 acres (1,861 acres) of reef.

China claims almost all of the vital waterway, where $3 trillion worth of trade passes annually, including parts claimed by the Philippines, Brunei, Malaysia, Taiwan and Vietnam.

But The Permanent Court of Arbitration in the Hague in 2016 found China's expansive claims in the South China Sea had no legal basis. Beijing does not accept the ruling.

The Philippine task-force, which warned of attempts by "Chinese experts" to sow disinformation and conduct malign influence, said it has evidence that China has been responsible for "severe damage to corals" in several areas in the South China Sea, including in Scarborough Shoal and Sabina Shoal.

Last year, the Philippines said it was exploring legal options against China, accusing it of destruction of coral reefs within its exclusive economic zone in the South China Sea, an allegation rejected by Beijing as an attempt to "create political drama".