North Korea has unilaterally informed South Korea that the minimum monthly wage of its workers at the inter-Korean Gaeseong Industrial Complex will rise five-point-18 percent next month to 74 dollars.

A Unification Ministry official told reporters Thursday that Pyongyang sent the notice to the Gaeseong Industrial Complex management committee on Tuesday.

While unilaterally notifying the South of its revisions to the factory part regulations made in December, the North also plans to raise the social insurance fees of South Korean companies operating in the industrial park to pay the North Korean authorities.

With the latest changes, the average real wage the South Korean companies pay to a North Korean worker is estimated to rise about eight-point-six dollars to 164-point-one dollars.

Responding to the North's unilateral notice, Seoul has sent a written notice under the name of the industrial park's joint committee head to express its regret. The South also asked for the North's cooperation to hold a inter-Korean joint committee meeting, but Pyongyang has rejected the notice.

The unification ministry official said it is highly regrettable that the North's joint committee administration office refused to receive the notice, adding that it is a violation of the administration's duties.

In November last year, North Korea has unilaterally revised 13 articles of labor regulations for the industrial complex that included removing the ceiling of the increase in minimum wage.