North Korea's human rights abuses should be dealt with more urgently than its nuclear or missile programmes, South Korean President Lee Myung-Bak said Wednesday.

Lee made the comment when he met a group of US lawmakers including Representative Ileana Ros-Lehtinen, the chairwoman of the House Foreign Affairs Committee, said presidential spokeswoman Lee Miyon.

"As to the North Korean issue, the human rights issue is no less important than nuclear tests or missile launches," the president was quoted as saying.

"The issue of human rights for the North Korean people should rather be dealt with more urgently (than tests or launches)," he said.

Ros-Lehtinen and five other Congress members arrived Tuesday in Seoul for a four-day visit that includes talks with President Lee and Unification Minister Yu Woo-Ik, as well as a trip to the border with the communist North.

Ros-Lehtinen has been outspoken against the North, initiating a series of bills aimed at putting it back on a US list of state sponsors of terrorism while also stressing the need to improve human rights.

The Republican congresswoman called the North Korean regime "one of the most brutal and dangerous in the world" and hailed Lee for "holding North Korea accountable for its serial violations."

"President Lee understands the sinister and duplicative nature of the regime in Pyongyang," Ros-Lehtinen said in a statement.

"He has rightly spoken out against North Korea's horrific human rights abuses and outlaw regime, and as a result has been targeted personally for verbal attacks. You know you are doing what is right if you are being attacked by the enemies of freedom, democracy and human dignity," she said.

Ros-Lehtinen said she had also voiced "outrage" to Lee over China's repatriation of North Korean defectors to their homeland, where activists say they face imprisonment or even execution.

Rights groups say that 150,000 to 200,000 prisoners are locked up in dire prison camps in North Korea. A report by South Korea's National Human Rights Commission found that many prisoners were incarcerated not for dissent but for trivial violations such as singing songs from the democratic South.

The US lawmakers' visit came amid lingering concern that Pyongyang could carry out a third nuclear test, after it lost face with a failed long-range rocket launch on April 13.

On Tuesday the North vowed to bolster nuclear deterrent capabilities and take "self-defence" measures as long as the United States continues what it called a hostile policy.

The UN Security Council strongly condemned last month's launch as breaching a ban on testing ballistic missile technology, and tightened existing sanctions.