Another flare-up in a maritime boundary dispute between China and Japan appears to have quickly subsided. Japanese officials say Beijing has clarified a ban on ships entering an area of the East China Sea straddling a disputed dividing line.

What could have been a significant escalation of the ongoing Sino-Japanese maritime border feud appears to have eased.

On March 1, China issued a seven-month ban on maritime traffic entering the waters over the Pinghu gas field in the East China Sea - including some of the area claimed by Japan.

Shinzo Abe

But Japan's chief cabinet secretary, Shinzo Abe, says Beijing has informed Tokyo that it will redraw the banned area so it does not affect the Japanese side of the disputed economic zone.

Abe says China has told Japan the notice was a technical error, and Tokyo believes it was just a simple mistake, but he questions why it took several weeks for the matter to be clarified.

The Chinese foreign ministry spokesman, Qin Gang, agreed the Chinese notice contained "technical inaccuracies." But he objected to Japanese comments on the issue.

Qin says China does not recognize the median line claimed unilaterally by the Japanese side, and he expresses dissatisfaction at what he calls "the Japanese practice of accusing China on the basis of their claim, and making an issue of this problem."

Japanese Foreign Minister Taro Aso took a tougher tone, than his counterparts in the cabinet, concerning the ban.

The foreign minister says it would have been common courtesy for China to notify other countries of the ban before or when it was implemented. He says the Japanese Coast Guard did not find out about it until the end of March.

Chinese spokesman Qin Gang, told reporters there was no need to inform Japan about the operation.

Qin says the actual area of operation is well within China's maritime territory, and China is exercising its normal sovereignty there. He says this is normal activity for China, so, he does not see any necessity to inform the Japanese side.

Despite repeated protests from Tokyo, China is working in the gas fields next to waters Japan claims for exclusive economic rights. China's wider territorial claim overlaps those waters.

Japan, in response to the Chinese exploration, has granted test-drilling rights to a Japanese company, although the company has not begun work. Foreign Minister Aso has threatened to take unspecified counter-measures if Beijing begins full-scale production.