The chief of South Korea's central bank on Wednesday hinted at lowering its 2015 growth estimate as downside risks have increased due to the expanding Middle East Respiratory Syndrome outbreak.

When questioned by lawmakers on the chances of trimming the Bank of Korea's 3.1 percent growth outlook, BOK Gov. Lee Ju-yeol said such a scenario is possible "under the current circumstances, if other factors do not occur."

The central bank is set to announce its revised economic outlook on July 9, when it also holds its monthly rate-setting meeting. In the latest economic update released in April, the BOK slashed its forecast to 3.1 percent from 3.4 percent.

Lee's remarks come as the unexpected MERS outbreak is feared to dent growth and consumption in Asia's fourth-largest economy that is already stuttering due to sagging exports.

In the few weeks following the first MERS outbreak on May 20, retailers have suffered double-digit falls in sales as people shun visits to public venues and foreign tourists cancel their travel plans on concerns of catching the illness.

Foreign investors have warned that the country's annual gross domestic product growth may drop as much as 0.8 percentage point if the outbreak continues for three months or longer.

As part of efforts to prop up growth and prevent the outbreak affecting sentiment, the central bank cut the key policy rate by a quarter percentage point last week, sending the rate lower to a fresh record of 1.5 percent.

The BOK governor, meanwhile, stressed that South Korea is unlikely to adopt a zero-rate policy as the country's macroeconomic circumstances, including consumer price inflation, do not require such a stance.

He also reiterated his view that it is up to the government to draw up a supplementary budget. Demand for a supplementary budget has been growing after the central bank delivered its June rate cut.

In a June 16 report, Nomura economist Kwon Young-sun said a supplementary budget worth 10 trillion won ($9 billion) may fully offset a 0.3 percentage point fall in growth spurred by MERS.

Regarding the U.S. Federal Reserve's rate cut expected later this year, Lee said the BOK will put the domestic economic situation on the front burner, hinting that the central bank will not immediately follow the U.S. rate normalization.

The BOK chief, meanwhile, voiced concern over the growing household debt, which has been on the rise in tandem with four rate cuts since last year that sent the key policy rate lower by a cumulative 1 percentage point.

"It is now time to come up with realistic and effective measures to prepare (for household debt)," he said.

In a separate report to the parliament, Financial Services Commission Chairman Yim Jong-yong said the financial watchdog will announce a package of measures in July to "strengthen its management" of the nation's household debt estimated to hover above 1,100 trillion won. (Yonhap)