China and Japan have resumed talks on maritime affairs, Chinese state media said Wednesday, a tentative sign that frosty relations may be beginning to thaw.

Yi Xianliang, deputy director-general of the foreign ministry's Department of Boundary and Ocean Affairs, met in the eastern coastal city of Qingdao Tuesday and Wednesday with his Japanese counterpart Makita Shimokawa, the official Xinhua news agency reported.

Both sides "agreed, on principle, to resume maritime liaisons between defence agencies of the two countries", it quoted a foreign ministry statement as saying.

Relations have plummeted to their lowest point in years, amid a series of rows over historical and territorial issues.

Some observers warn that the Asian giants might come to blows over an East China Sea island chain -- called the Senkakus by Japan and the Diaoyus by China -- where ships from both sides lurk to press claims for ownership.

Beijing has laid the blame for the tensions on Japan, which in September 2012 nationalised the archipelago. Japan contends that China's claim has no historical basis and that it is trying to challenge Tokyo's rule through military intimidation.

Beijing also sparked regional controversy -- as well as condemnation from Washington -- late last year with its unilateral declaration of an Air Defence Identification Zone which overlaps territory claimed by Japan.

The first China-Japan high-level maritime talks were held in May 2012 in the eastern city of Hangzhou.

According to Xinhua, officials from both countries on Wednesday agreed "on principle" to hold their next round of talks late this year or early next year.