The Korea Composite Stock Price Index (KOSPI) was up 0.42 percent at 2,080.92 points as of 0121 GMT.

"The market keeps moving up gradually and will continue to do that for a while," said Lee Seon-yeob, a market analyst at Shinhan Investment Corporation.

Foreign investors continued picking up shares, albeit a modest net 48.6 billion won, poised to buy for an 11th straight session, the longest buying streak in more than six months.

"The Japan nuclear accident factor seems to have little negative impact and concerns over Eurozone debt are easing," Lee said.

Shipbuilders led the market higher.

Daewoo Shipbuilding & Marine Engineering Co Ltd , the world's No.2 shipyard, advanced 2 percent after its senior executive said Japan's lost nuclear capacity could be a catalyst to strong LNG orders ahead.

Hyundai Heavy Industries Co Ltd climbed 1.5 percent.

Carmakers edged higher with the country's top automaker Hyundai Motor touching a new record high, up 0.7 percent.

Kia Motors Corp gained 0.6 percent

Mask makers jumped on reports that fears over radiation from Japan's nuclear incidents had boosted sales.

Clean&Science jumped the intraday limit of 15 percent and Welcron surged 8.5 percent.

Energy issues bucked the upward trend, retreating after recent gains on rising oil prices.

SK Innovation fell 0.7 percent and S-Oil Corp lost 1.3 percent.