The Bank of Korea, the central bank, said financial firms from next Monday would be barred from subscribing to public offerings of so-called kimchi bonds if the issuer intends to swap the proceeds into won.

Local companies sometimes issue kimchi bonds to raise dollars for settlements with US trading partners.

But the central bank said many firms were in fact issuing such bonds to get around rules on banks' foreign loans. "Companies have been using about 70 percent of the bonds for won use in Korea," it said in a statement.

By law, banks can only issue foreign-currency loans if the borrower needs the money for overseas use.

Financial firms will still be allowed to buy such bonds if they are intended for overseas foreign-currency use.

The announcement marked the latest attempt by authorities to ease the destabilising effect of so-called "hot money".

The country has seen a surge of foreign capital into its markets, amid solid economic growth and expectations of a stronger won. This has raised fears that the foreign cash could exit just as swiftly, as it did during the 1997-1998 East Asian financial crisis and the 2008 global crisis.

South Korea's short-term foreign debt stood at $146.7 billion as of the end of March, up $11.7 billion from three months earlier and marking the largest quarterly growth in over two years.

The government has already capped banks' foreign-exchange forward positions to try to curb speculative bets on the won, which has risen six percent this year against the dollar.

It has also brought in a tax on foreign investment in local bonds and a levy on banks' offshore borrowings.

Authorities are concerned that kimchi bonds have been used as a way of getting cheaper loans, creating unnecessary exchange-rate risks, instead of meeting actual foreign-currency needs such as settling contracts.

As of the end of June, outstanding kimchi bonds stood at about $17.05 billion. About 77 percent of the total was held by the local branches of foreign banks operating in Korea, according to central bank data.

Copyright AFP (Agence France-Presse), 2011