The president promised the move in an election pledge

Government and administrative functions will be moved, and possibly parliament and the supreme court.

The potential new sites are all in the centre of the country - it is hoped the move will ease regional rivalry and re-balance Seoul's economic dominance.

But opposition parties have called for a referendum, saying the plans go further than originally announced.

President Roh Moo-hyun confirmed the move on Tuesday.

"It is one of the core projects of the participatory government", he told his cabinet according to South Korean news agency Yonhap.

The decision to move fulfils a campaign pledge made by Mr Roh before elections in 2002.

South Korea is following other nations in choosing its capital through compromise.

Queen Victoria picked Ottawa as Canada's capital after a dispute between various cities, and Canberra became capital of Australia because it was not Melbourne or Sydney.

The four South Korean candidates are Eumseong/Jincheon in North Chungchong province, and Chonan, Yeongi/Kongju and Kongju/Nonsan, all in South Chungchong province.

COMPROMISE CAPITALS Canberra, Australia Brasilia, Brazil Washington DC, US Ottawa, Canada Abuja, Nigeria

The winning candidate will be announced in August, the Presidential Committee on Administrative Capital Relocation announced.

Construction of the new capital, which will house an expected 500,000 people, is scheduled to start in 2007, with relocation due to begin in 2012 and completion in 2030.