South Korea will step up itsmonitoring of any speculative movement in the financial markets, the finance ministry said Friday, amid worries over the local currency's fast ascent against the greenback.

"The government will intensify its market monitoring to see if there is any speculative movement in foreign capital flows and transactions in the non-deliverable forward market in relation to recent currency exchange rates," the ministry said in a message sent to reporters.

The ministry added that the government will take "stern" action against speculative forces that cause herd behavior in the market, sending a signal that it could intervene in cases in which there's one-sided movement in currency exchange rates.

The verbal intervention comes as concerns are growing that the won's continued ascent against the U.S. dollar might result in hurting the country's exports and dampening the fragile economic recovery.

The local currency closed at 1,022.50 won against the greenback on Wednesday, the highest level since Aug. 7, 2008. The won was trading at 1,023.5 won against the greenback as of 1:30 p.m., up 2.1 won from the previous day's close. (Yonhap)