Japanese military authorities are trying to play up the China threat theory as an excuse for the country's military expansion, Chinese experts said after a media report on Japan's forthcoming defense white paper.

The white paper, to be submitted to the Japanese Cabinet for approval early next month, is expected to say that Beijing's activities in the South China Sea are making its territorial claims a fait accompli, according to Kyodo News, which said it had obtained an outline of the paper.

"We have noticed the report, and the situation still needs to be verified and considered," the Ministry of National Defense told China Daily on Wednesday.

The outline, according to the report, says China's activities are intensifying near the Diaoyu Islands in the East China Sea.

A Chinese navy ship last month sailed in a "contiguous zone" just outside territorial waters around the Diaoyu Islands, Kyodo quoted the outline as saying.

The outline also says that the number of times that Japan has scrambled fighter jets against Chinese aircraft approaching its airspace has risen sharply, according to Kyodo.

Zhang Junshe, a senior researcher at the PLA Naval Military Studies Research Institute, said that Japanese military authorities have been trying to play up China's threat in recent years, and the white paper "is telling the same lies" as before.

China's military drill in the South China Sea, lasting from Tuesday to Thursday, took place on China's own maritime territory and is done for self-defense purposes, he said.

"The recent Japan-Philippine military exercise took place in the South China Sea, quite far from Japanese homeland, so who on Earth is flexing muscles?" he said, adding that most of Japan's military drills targeted China as a potential enemy.

The Japanese Navy carried out a joint military exercise with the Philippines on July 13, the day after the announcement of the ruling by the Arbitral Tribunal of The Hague.

Jin Yong, a professor of international relations studies at Communication University of China, said that through exaggerating China's military threat, Japan is "playing the trick of a thief crying 'Stop, thief'!"