Rep. Na Kyung-won of the ruling Grand National Party on Friday made her Seoul mayoral bid official, a month ahead of the by-election.

Na, elected to one of the seven members of the GNP’s supreme council in July, is expected to vie against former minister of government legislation Lee Seog-yeon, who announced his bid days earlier, to contest the opposition.

Polls so far showed that civic activist and lawyer Park Won-soon currently runs ahead of other opposition mayoral hopefuls, a month ahead of the vote.

In a survey of 3,700 Seoul voters jointly conducted by Yonhap News agency and a group of 12 political poll takers, Park was leading Na by up to 18 percentage points.

Park’s supporting rates ranged between 42.6 percent 51.5 percent, according to the polls, which used wired telephones, mobile phones as well as automatic answering systems. Between 30.8 percent and 36.6 percent of the respondents said they support Na.

In response to a question on her outlook of the ruling bloc’s unified candidacy, Na said the values sought by Lee and civic groups won’t be “much different” from that of the GNP.

Lee said in a radio interview Friday that he believed the governing bloc should field a unified candidate to vie against the opposition which is set to pick a single contender.

About the use of survey results in selecting a unified candidate, Lee said they would constitute “important criteria,” but should not be entirely depended on.

Lee stressed that it would be hard for the GNP, which he said was urging him to join the party for an internal race, to get the voters sympathize if they stick to old rules for the internal race.

Lee vowed Friday to spend only a tenth of the legally permitted campaign money by working with volunteers and family members.

Lee prides himself on having “defended the capital” by filing a constitutional petition in 2004 to block the government plan to move central government agencies to Sejong City in South Chungcheong Province. The Constitutional Court ruled the plan unconstitutional, resulting in relocation of about two thirds of government ministries.

By Kim So-hyun (sophie@heraldcorp.com)