SEOUL - South Korea will issue navigation warnings to ships operating in its territorial waters to protect them as the Democratic People's Republic of Korea (DPRK) readies itself for a controversial rocket launch, the government said Tuesday.

Alert announcements will be made every two hours starting Wednesday through Sunday, with the country's 15 maritime traffic control centers on alert, the Ministry of Land, Transport and Maritime Affairs said.

It said the first stage of the rocket is expected to fall into waters some 170 kilometers west of the western port city of Gunsan.

The DPRK plans to launch a rocket-mounted satellite sometime between April 12-16 to mark the birth centennial on April 15 of the country's founding father Kim il-sung.

South Korea and the United States, among others, call the launch a disguised long-range ballistic missile test that breaches a United Nations ban.

South Korea and Japan have said they will shoot down the rocket if it strays into their territories, while the DPRK warned of "merciless punishment" for such attempts.