SEOUL, April 2, 2008 (AFP) - South Korea's conservative party is poised to win a big majority in next week's parliamentary election, helping new President Lee Myung-Bak enact sweeping economic changes, opinion polls showed Wednesday.

Lee's Grand National Party (GNP) will win 144 of the 245 directly elected seats in the National Assembly compared to 71 for the liberal United Democratic Party (UDP), according to the polls published in JoongAng Ilbo newspaper.

Independents would win 16 seats, the rightist Liberty Forward Party nine and other minority parties five, according to a joint poll by the paper and YTN television and a survey by polling firms.

The other 54 seats in the 299-member legislature are allotted by proportional representation depending on each party's share of the vote.

In February, before a series of breakaways by members who failed to secure nominations, the GNP had 130 seats to 135 for the UDP.

The UDP and its allies used their majority to persuade several of Lee's cabinet nominees to withdraw.

The former CEO, who has pledged to revitalise the world's 13th largest economy through tax cuts, deregulation and privatisation, needs a GNP majority to help enact his programme.

Despite being on course for victory, his party's hopes of winning two-thirds of the assembly have faded due to a deep internal split between Lee's supporters and followers of his party rival Park Geun-Hye.

Park has announced she will not campaign for party candidates, in protest at the exclusion of many of her own supporters from the nomination list. Many of these have bolted the GNP to form a 'Pro-Park Alliance,' which has fielded 65 candidates.

The UDP, which was trounced in the December 19 presidential election, says it hopes to win at least 100 parliamentary seats so it can stop any moves by the GNP to change the constitution.

The JoongAng-YTN joint survey questioned 500 people by phone in each geographical constituency from March 29-31. The margin of error was plus or minus 4.4 percentage points.