Yen futures trading in South Korea has spiked so far this year as more investors make bets on the further descent of the Japanese currency, data showed Tuesday.

The daily turnover of yen futures has reached an average of 104.9 billion won ($98.7 million) in the Seoul market as of last Friday since the beginning of this year, up 84.9 percent from the average 56.7 billion won tallied over the same period in 2012, according to the data by the Korea Exchange (KRX).

A foreign exchange futures contract refers to buying or selling a specified amount of a given currency at a predetermined price on a set date in the future. It is a common hedging tool used by companies to avoid risks in cross-rate transactions.

Investors have usually bet on the yen's rise, as the currency is considered a safer asset. But with its fast depreciation against other global currencies, local foreign exchange market has seen a spike in yen futures betting on its fall.

In January alone, its daily turnover spiked 97.8 percent to 8,765 contracts, compared with 4,432 deals a month earlier, KRX data showed.

The surge in yen futures trading came as investors became more certain that the currency will continue its weakening streak for some time, largely due to the pledge by its new government, headed by Shinzo Abe, for an "infinite" expansion of monetary easing to fuel growth.

Earlier in the day, the Bank of Japan (BOJ) said it will push for open-ended asset purchases from 2014 as part of an aggressive approach to fuel growth, setting its inflation target at 2 percent for 2013, as it ended its two-day policy meeting.

Abe recently signed a fresh stimulus measure worth 20 trillion yen ($225.9 billion) to overcome the chronic deflation the country has been facing for decades.

"Since late last year, expectations for a powerful monetary easing policy have prompted futures bets on a weaker yen," said Park Yu-na, an analyst at Dongbu Securities Co.

The cross-rate between the yen and U.S. dollar breached the 90 yen mark as of Jan. 18, for the first time since June 2010.

On the Seoul market, the Korean won was changing hands at 1,189.34 won per 100 yen as of 1:17 p.m., down 4.11 won from Monday's close. (Yonhap News)