S.Korea completes world's longest seawall

South Korea inaugurated Tuesday the world's longest seawall, the first step in a massive project aimed at reclaiming the ocean for industry, tourism and agriculture by 2020.

The 33 kilometre (21 mile) Saemangeum seawall encloses 401 square kilometres (160 square miles) of seawater, about two thirds of Seoul's land area.

The government has already spent 2.9 trillion won (2.6 billion dollars) on what is billed as the country's largest-ever development project, despite environmental concerns.

Another 21 trillion won in state and private spending is envisaged until 2020 to reclaim land, build infrastructure and create giant freshwater reservoirs.

The project was first mooted in the early 1970s and work on the west coast dike 280 kilometres south of Seoul began in 1991.

Originally, the government planned to use most of the reclaimed land for farming but the country's rice production now outstrips demand.

The plan now is to build a new city focused on logistics, industry, tourism and leisure as well as floriculture.

The reclaimed area and the port city of Gunsan will jointly house an international business complex to be called the Saemangeum-Gunsan Free Economic Zone by 2020.

The project has been dogged by fears of environmental disaster, and was marked by protests and clashes with riot police.

Environmentalists say it will destroy huge mudflats providing habitats for wildlife and serving as natural water purification plants.

Opposition eased somewhat as authorities promised to invest more to address environmental concerns, including tighter control of pollution upstream on the two rivers that flow into the area.

"However, the overall development project must be reviewed in order to preserve the mudflats as much as possible," Jee Woon-Geun, a director of the Korean Federation for Environmental Movement, told AFP.

"Mudflats enable sustainable development. They are also a great tourist attraction."