The Philippine and Vietnamese coast guards held firefighting and search-and-rescue exercises off Manila on Friday, the first such drills between the two countries with maritime disputes with Beijing in the South China Sea.

The Philippines and Vietnam both claim part of the strategic waterway's Spratly archipelago, but said the drills at the mouth of Manila Bay contributed to maintaining peace and stability in the contested sea. 

"It's a good thing that we are going in one direction, which is the rules-based approach of the Philippines," Lawrence Roque, captain of the Philippine ship BRP Gabriela Silang, told reporters following the drills.

"We hope also that the Vietnam Coast Guard, particularly the Vietnamese government, will also... follow the Philippines in enhancing or following the rules-based approach," he added.

The Gabriela Silang and Vietnam's CSB 8002 vessel fired water cannon at a second Filipino vessel to simulate the rescue of a boat on fire in choppy waters at the mouth of the bay, which opens into the South China Sea.

A Filipino helicopter then dropped orange dummies into the sea as the two vessels launched tiny rubber boats which bobbed violently above the metre- (3.3-foot) tall waves to retrieve the make-believe victims.

The crews stood on deck and saluted each other as the two vessels did a passing manoeuvre to conclude the drills.

"We hope this will be the start of many more exercises of this type," Roque added.

The exercise stood in stark contrast to violent confrontations between Philippine and Chinese government vessels in recent months which have fuelled fears of a conflict that could drag in the United States, a Manila ally.

Beijing claims almost the entire South China Sea, brushing off rival claims of several Southeast Asian countries, including the Philippines, and an international ruling that its assertion has no legal basis.

One of the most serious incidents took place in June, when Chinese sailors brandishing weapons including knives and an axe boarded Philippine naval vessels during a resupply mission to Filipino-held Second Thomas Shoal.