China has said it took "control measures" against Philippine ships it accused of "illegally gathering" near a disputed reef in the South China Sea in recent days.

"Recently, several Philippine ships ... illegally gathered under the pretense of fishing in the waters near Houteng Reef of China's Nansha Islands," China Coast Guard spokesperson Liu Dejun said in a statement Monday, using the Chinese names for the Iroquois Reef and Spratly Islands.

"The China Coast Guard took necessary control measures against the Philippine ships in accordance with the law," Liu said.