[SEOUL] South Korea's former top prosecutor whose battles with President Moon Jae-in made him one of the country's most popular political figures launched a bid to seek the top job himself.

Yoon Seok-youl - who was appointed prosecutor-general by Mr Moon before feuding with the administration and resigning - said in a national televised news conference Tuesday he cannot let the policies of the Moon government stand and announced he intends to run for the job in elections in March.

Mr Moon "divided our nation and threw away our value of the rule of law," Mr Yoon said. He also criticised the administration for having "economic policies that ignored common sense" and housing policies that fought against the market.

Mr Yoon didn't declare if he would align himself with a political party but members of the conservative opposition People Power Party have been urging him to run under their banner.

South Korea is heading toward what may be its most wide-open presidential race since the advent of full democracy in the late 1980s. Mr Moon has no clear successor and no current PPP members poll as well for the presidency as Mr Yoon, who is not a party member.

Mr Yoon helped lead an investigation that led to the impeachment of conservative President Park Geun-hye in 2016. He has emerged in opinion polls as the top-ranked candidate to take over from Mr Moon when his single, five-year term ends. Mr Yoon's ascension in popularity comes as conservatives look to take back the presidential Blue House, seeking to attract younger voters who believe the current system favors the powerful and politically connected.

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The election will likely be fought over populist policies to narrow an income inequality gap that ranks among the widest in the developed world and rein in real-estate prices that have left urban housing out of reach for many. Mr Moon pledged to make housing more affordable when he was elected in 2017, but apartment prices in Seoul have doubled in the last five years and property speculation scandals with members of his government have stoked anger.

While Mr Yoon was handpicked by Mr Moon to lead a campaign against corruption, he later faced a backlash from the president for launching probes that helped force out two justice ministers. Mr Yoon, who resigned in March, has given little indication so far what he might do in terms of policy if he became president.

"Security, the economy, domestic problems and international relations have now become inseparable. Now, war is not fought with guns, but with semiconductor chips," Mr Yoon said at the news conference.

The top-ranked candidate for Moon's Democratic Party, Gyeonggi province Governor Lee Jae-myung, has gained support for his signature policy of universal basic income, saying without across-the-board income support to address inequality, the stability of the country's economy could be threatened. A PNR Research survey Sunday showed 32.7 per cent of respondents preferred Mr Yoon as the next president, with Mr Lee next about 7 percentage points behind.

Two other people who served in Mr Moon's government are also gearing up for a presidential run against the ruling party. Choe Jae-hyeong - who has clashed with Mr Moon over nuclear power plants - resigned as Board of Audit and Inspection chairman on Monday to make a bid for presidency.

Mr Moon's first finance minister, Kim Dong-yeon, is also being considered as a potential opposition candidate.

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