A Japanese media report accusing the Chinese navy of "ignoring" a requirement to inform Japanese counterparts of their presence in certain areas of the East China Sea was "not in accordance with the facts", a source within the Chinese Ministry of National Defense told China Daily on Tuesday.

Seven Chinese navy warships sailed through the Miyako Strait between Okinawa Island and Miyako Island in Okinawa Prefecture on Oct 4, according to the Kyodo News Agency, quoting the Japanese Defense Ministry.

The Chinese vessels were actually passing through international waters en route to the Pacific Ocean.

But leading Japanese newspaper Sankei Shimbun claimed on Monday the Chinese ships had not informed Japanese officials beforehand, and the move ignored an agreement between the countries to inform each other of any military movements through the strait.

Sankei said defense authorities on both sides this summer had reached an overall consensus on a "crisis management mechanism".

But a Ministry of National Defense official, who is familiar with the issue but declined to be named, denied the two countries' defense authorities had established such a mechanism, and said there is no agreement in place to inform each other of military traffic.

"The report does not reflect the facts," the official said.

Yin Zhuo, a Beijing-based military expert, said the Chinese ship movements were within international rules, and that Tokyo tends to view the presence of any Chinese navy ships in the East China Sea as a "threat".

Relations between Japan and China have been strained since Japanese coast guard vessels collided with a Chinese fishing boat in the waters off the Diaoyu Islands in September 2010.

In May, China and Japan held the first round of high-level consultations on maritime affairs in Hangzhou, East China's Zhejiang province, and both sides agreed on the need for a mechanism to deal with any potential future incidents.

The latest diplomatic stand-off between the two countries escalated on Sept 11 after the Noda Cabinet finalized an illegal "purchase" of the Diaoyu Islands, which have belonged to China for centuries.

Beijing has since lodged a series of protests with Tokyo and taken counter measures to reaffirm sovereignty over the uninhabited islands.

Chinese maritime administration and fishery administration vessels have been patrolling the waters off the Diaoyu Islands, a move that Sankei said has "overshadowed" the signing of any crisis management mechanism.