SEOUL, Sept. 22 (Yonhap) -- South Korea's top financial regulator said Thursday the potential outflow of foreign capital is the biggest concern for the South Korean economy, which is highly vulnerable to external uncertainties.

"The rapid outflow of foreign capital is the area we are most worried about … Financial institutions may face difficulties in revolving short-term foreign debts, a situation that resembles the 2008 global financial crisis," Financial Services Commission (FSC) Chairman Kim Seok-dong said in a radio interview.

Kim said the country's economy, Asia's fourth-largest, is receiving "big shocks" from the ongoing global economic slowdown due to its openness.

The top regulator said the woes stemming from the eurozone debt crisis, coupled with a recession in the real economy, may last for a "quite long" period due to unclear solutions and a rocky process toward international cooperation.

Meanwhile, the regulator stressed no more savings banks face business suspensions within this year unless unexpected situations occur.

The FSC on Sunday suspended seven players with heavy debts and inadequate liquidity ratios as part of its efforts to overhaul the struggling sector, raising concerns the move will trigger a massive deposit withdrawal.

Kim said the financial regulator will step up supervision of the ailing sector and request that savings banks post financial statements on a quarterly basis instead of the previous six-month basis.