The central bank's monetary policy board is widely expected this week to take the first-ever "big step" of raising the key rate by zero-point-five percentage points.

The move comes after the Bank of Korea's(BOK) rate-setting committee unanimously elected to increase the rate by 25 basis points in late May, the second consecutive quarter to feature such a hike after the one in April.

Should the board further raise the rate from the current one-point-75 percent during Wednesday's meeting, it would be the first time that it adjusts the rate upward three consecutive times.

According to industry sources and experts on Tuesday, such a move is predicted in light of rising inflation, which hit six percent on-year in June amid soaring global raw material and crop prices.

Also behind the BOK's "big step" is an attempt to prevent the U.S. benchmark interest rate from surpassing South Korea's if and when the Federal Reserve takes its own "big step," or even "giant step," of a zero-point-75-percentage point hike.

Some analysts, however, predict that the central bank will not push ahead with the 50-basis-point hike, warning that a rapid rate increase could lead to sluggish consumption and economic stagnation.