Kakao Bank headquarters in Seongnam, Gyeonggi Province / Yonhap

Unionized workers at internet-only Kakao Bank launched a full-scale strike Friday over wage increases and other benefits, its union said.

The labor union and Kakao Bank's management have been in negotiations over a pay raise and other benefits but failed to narrow differences.

According to the union, over 700 unionized workers participated in the one-day strike but did not hold a rally.

"We are discussing our future actions," the union said.