South Korea's foreign ministry on Tuesday expressed "grave concerns" over China's recent use of water cannons against Philippine ships, saying it stokes tension in the South China Sea and undermines a maritime order.

The Philippines accused China's coastguard of using water cannons on Saturday against a civilian boat supplying troops at the Spratly Islands, a largely uninhabited archipelago in the South China Sea which has long been a source of territorial spats between the two countries.

It was the latest in a series of flare-ups in the past year.

The Philippines lodged a protest and said the boat was damaged and some crew injured, while Beijing warned Manila to behave cautiously and seek dialogue, saying their ties were at a "crossroads".

"We are gravely concerned about the recent and repeated use of water cannons in the South China Sea," Seoul's foreign ministry spokesperson, Lim Soo-suk, told a briefing.

"These actions increase tensions in the South China Sea, a major international navigation route used by all countries including Korea, and undermine efforts to maintain peace, stability, security and a rules-based maritime order."

He also said the freedom of navigation and overflight must be respected by all countries based on international law.

South Korea's Yoon Suk Yeol administration has been vocal about tension in the South China Sea and also the Taiwan Strait, saying it opposes attempts to change the status quo by force.

(Reporting by Hyonhee Shin; Editing by Michael Perry)