South Korea has announced an expanded air defence zone partially overlapping a region claimed by China, further raising the stakes in the ongoing regional tensions in East China Sea.

South Korea's newly declared zone includes a submerged rock, which is also claimed by China.

"We believe this will not significantly impact our relationships with China and with Japan as we try to work for peace and co-operation in north-east Asia," the South Korean defence ministry's chief of policy Jang Hyuk told reporters.

He added that South Korea prioritises smooth relations with its neighbouring countries to prevent any military confrontation.

"We have explained our position to related countries and overall they are in agreement that this move complies with international regulations and is not an excessive measure."

The new zone will come into effect on 15 December. A key ocean research station, Leodo, on a submerged reef is also being included in Seoul's declaration.

The defence ministry added: "The air defence and identification zone adjustment is in line with the international aviation order and international regulations. It does not put restrictions on civilian flight operations or infringe upon the airspace and interests of neighbouring countries."

"Ahead of today's announcement, we have offered sufficient explanations to related countries. The government will discuss with related countries measures necessary to prevent accidental military clashes within the newly adjusted air defence and identification zone."

Neither the US nor China has responded to South Korea's latest announcement.

On the eve of the announcement, however, Beijing said any declaration by South Korea "should comply with international laws and conventions".

China had earlier reignited a territorial row with Japan and South Korea by unilaterally announcing an air-defence zone over disputed areas.