North Korea on Saturday threatened to use a "powerful nuclear deterrence" in response to a South Korea-US joint naval exercise, state media said.

North Korea was prepared for a "retaliatory sacred war", the Korean Central News Agency (KCNA) said, quoting Pyongyang's National Defence Commission.

The United States and South Korea have announced joint naval exercises, beginning on Sunday, in what they said is a bid to deter North Korea's "aggressive" behaviour.

"All these war manoeuvres are nothing but outright provocations aimed to stifle the Democratic People's Republic of Korea by force of arms to all intents and purposes," KCNA said, using North Korea's official name.

"The army and people of the DPRK will legitimately counter with their powerful nuclear deterrence the largest-ever nuclear war exercises to be staged by the US and the South Korean puppet forces."