The powerful sister of North Korean leader Kim Jong-un on Tuesday denounced "political agitation" leaflets, accusing South Korea of sending them across the border.

"Various kinds of political agitation leaflets and dirty things sent by the ROK scum were dropped again in different areas near the southern border of the DPRK" on Tuesday, the North's Korean Central News Agency quoted Kim Yo-jong as saying in a statement.

ROK stands for the Republic of Korea, the official name of South Korea, while DPRK stands for the Democratic People's Republic of Korea, the official name of North Korea.

Security forces organs have blocked the affected areas and were searching for, gathering and disposing of the materials, she said.

"We strongly denounce the despicable acts of the ROK scum who committed the provocation of polluting the inviolable territory of the DPRK by scattering anti-DPRK political and conspiratorial agitation things again," the statement said.

Last week, Kim accused South Korea of sending anti-Pyongyang leaflets to the North and warned that the South would pay a "dear price." This was followed by the North launching trash-filled balloons across the border into the South.

North Korea has reacted angrily to South Korean activists sending balloons across the border carrying anti-Pyongyang propaganda leaflets and South Korean consumer goods. (Yonhap)