It marked the first turnaround in three months, as the index had slid since October.

The BOK said many people expected their earnings to rise next year.

"Increasing minimum wage may have affected the optimistic atmosphere to some extent," said a BOK official.

The South Korean government set the minimum wage at 8,350 won ($7.42) per hour for next year, up 10.9 percent from this year's level, as part of its income-led growth policy.

But the index measuring people's sentiment regarding current economic conditions, one of key components for the index, remained flat at 62 in December. Their assessment of overall economic conditions for the next six months was also unchanged at 72.

The BOK monthly index for December was based on a survey of 2,172 households throughout the country and was conducted from Dec. 11-18. (Yonhap)