South Korea will spend $2.3 billion dollars over the next five years to secure tactical weapons targetting North Korea's nuclear weapons facilities and missile bases, a state agency said Tuesday.

The defense ministry has approved a five-year plan to spend 2.7 trillion won ($2.3 billion) on buying hundreds of home-built ballistic missiles and other weapons, the Defence Acquisition and Procurement Agency said.

It needs parliamentary approval to be implemented.

In April, the South unveiled a new cruise missile dubbed "Hyunmu-3", which can travel more than 1,000 kilometres (625 miles).

The military plans to increase the number of its Hyunmu-3 cruise missiles as well as the number of Hyunmu-2 ballistic missiles, which have a 300-km range.

South Korea also wants the United States to expand the range of Seoul's ballistic missiles.

The US stations 28,500 troops in South Korea, a close ally, and guarantees a nuclear "umbrella" in case of any atomic attack. In return, Seoul maintains a 300-kilometre limit on its missile capabilities.

The need to strengthen Seoul's missile capability took on new urgency after the North's latest long-range rocket launch in April.

The South believes the North has 1,000 missiles of various types, many of them targeted at Seoul or other locations in the South.