The possible US deployment of a missile defence system on the Korean peninsula in response to Pyongyang's ballistic missile programme would threaten China's strategic interests, Beijing said on Monday.

Washington and Seoul will begin talks about the Terminal High Altitude Area Defence System (THAAD), they said a week ago following a surprise nuclear test and satellite launch by the hermit kingdom that raised fresh concerns about its weapons ambitions.

"We are firmly opposed to the relevant country's attempts to damage China's strategic and security interests, with the nuclear issue as an excuse," foreign ministry spokesman Hong Lei told a regular briefing.

China was "seriously concerned about the possible deployment of the THAAD system", he added, saying it "covers a range that is far beyond the needs of defence of the Korean peninsula".

Beijing argues that the THAAD deployment would trigger an arms race in the region.

The system fires anti-ballistic missiles into the sky to smash into enemy missiles either inside or outside the Earth's atmosphere during their final flight phase.

The interceptor missiles carry no warheads, instead relying on kinetic energy to destroy their targets.

China summoned the South Korean ambassador in Beijing following the country's announcement that it would begin talks with the US, expected as early as this week.

"We will not allow our legitimate rights and national security interests to be damaged," Hong said.

China has long urged a resumption of talks over North Korea's nuclear programme, arguing that sanctions are not an end in themselves.

The government-published China Daily said in an editorial Monday that new United Nations measures "should truly bite" -- but added that the proposed THAAD deployment could prevent agreement on a resolution.

The potential collapse of North Korea is a perennial worry for Beijing, which sees it as a buffer against the US military presence in South Korea and worries that instability could unleash a flood of refugees across its border.

Washington says it will not sit down with Pyongyang until the country takes steps towards halting its nuclear programme, a position that Beijing argues has led to the current impasse.

For its part, the US has long called for Beijing to use its role as one of Pyongyang's most important economic lifelines to pressure the country into changing its behaviour.