The Democratic People's Republic of Korea (DPRK) notified South Korea of its unilateral decision to raise minimum wage for DPRK workers employed by South Korean companies at the joint factory park in the DPRK border city of Kaesong, Seoul's unification ministry said Thursday.

Unification Ministry spokesman Lim Byeong-cheol told reporters that the DPRK sent a notice in the afternoon to the Kaesong industrial complex management committee saying that it unilaterally decided to raise monthly minimum wage for workers from March 1.

Under the decision, the minimum wage would rise from 70.35 US dollars per month to 74 dollars, representing a 5.18 percent increase.

Previously, the pay hike rate was decided through talks between the two Koreas. The ceiling to the hike rate was limited to 5 percent per year according to the inter-Korean agreement, the ministry said.

The DPRK also said it will raise "social insurance fee" for its workers, which are paid by South Korean companies to the DPRK authorities.

Including the higher minimum wage and social insurance fee, an average monthly wage for DPRK workers in the Kaesong industrial zone is expected to total 164.1 dollars, up 5.53 percent from the current 155.5 dollars.

South Korea expressed deep regrets over the "unilateral" decision, expecting to instruct companies in the Kaesong complex to pay the same as before. The March wage is scheduled to be paid to DPRK workers between April 10 and 20.

The spokesman said it is not a matter of how much is paid to workers, but a matter of why DPRK workers should unilaterally decide on how much they are paid, adding that talks between the two Koreas would be necessary to resolve the issue.