The remarks by Foreign Minister Wang Yi came at an ASEAN Regional Forum (ARF) overshadowed by disputes over the strategically significant sea.
Beijing claims it almost in its entirety, putting it at odds with countries including the Philippines and Vietnam, and there have been several tense encounters in the area over recent months.
US Secretary of State John Kerry appeared at the forum to push for a multilateral agreement to end all actions that risk further inflaming regional sensitivities.
"China and ASEAN are totally able to safeguard well the peace and stability of South China Sea."
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His comments, posted on the foreign ministry's website today, were aimed squarely at the US, state-run media said.
China's official Xinhua news agency headlined its report on his comments: "China rebuffs US 'freeze' proposal on South China Sea."
It said Wang repeated China's long-standing rejection of multilateral talks over the sea, saying that "relevant disputes should be addressed by countries directly concerned".
"By stoking the flames, Washington is further emboldening countries like the Philippines and Vietnam to take a hardline stance against China," it said.
"It is a painful reality that Uncle Sam has left too many places in chaos after it stepped in, as what people are witnessing now in Iraq, Syria and Libya," it added.
"The South China Sea should not be the next one."
At the ARF, Kerry on Saturday formally put forward Washington's proposal to cool maritime tensions based on claimant states agreeing to step back from actions that could "complicate or escalate disputes".