Construction work by China on some garrisoned islands and reefs on its Nansha Islands was defended by a senior Chinese diplomat on Tuesday.

Such work is proceeding "at a pace and on a scale befitting its (China's) international responsibilities and obligations", the diplomat said.

Ouyang Yujing, director-general of the Chinese Foreign Ministry's Department of Boundary and Ocean Affairs, was responding to accusations that China's construction activities on some islands and reefs are outpacing and "outsizing" those by other countries in the South China Sea.