SEOUL (Reuters) - Shares in Korea Zinc fell as much as 29.9% to their daily lower limit in Wednesday's trade, after the company announced a capital increase by issuing new shares worth 2.5 trillion won ($1.81 billion).

Korea Zinc said in a regulatory filing its board decided on Wednesday to issue some 3.73 million shares at 670,000 won per share. This was 57% lower than Tuesday's closing price of 1,543,000 won.

Korea Zinc said out of the 2.5 trillion won in funds to be raised, 2.3 trillion won would be used to pay off debt.

The new shares will be listed on Dec. 18, the filing said.

($1 = 1,382.9400 won)

(Reporting by Joyce Lee; Editing by Ed Davies)