SEOUL  South Korean President Yoon Suk Yeol offered on Thursday to establish a working-level consultative body with North Korea to discuss ways to ease tension and resume economic cooperation, as he laid out his vision on unification of the neighbours.

In a National Liberation Day speech marking the 79th anniversary of independence from Japan's 1910-45 colonial rule after World War Two, Yoon said he was ready to begin political and economic cooperation if North Korea "takes just one step" toward "denuclearisation".

Yoon used the speech to unveil a blueprint for unification and make a fresh outreach to Pyongyang, following his government's recent offer to provide relief supplies for flood damage in the isolated North which he said had been rejected.

But a unified Korea appears a distant prospect with relations between the neighbours at the lowest point in decades as North Korea races to advance its nuclear and missile capabilities and takes steps to cut ties with the South, redefining it as a separate, hostile enemy state.

At the start of the year, North Korean leader Kim Jong Un called South Korea a "primary foe" and said unification was no longer possible.

Yoon said launching the "inter-Korean working group" could help relieve tensions and handle any issues ranging from economic cooperation to people-to-people exchanges to reunions of families separated by the 1950-53 Korean War.

"Dialogue and cooperation can bring about substantive progress in inter-Korean relations," he said.

In Washington, the White House senior director for the East Asia region, Mira Rapp-Hooper, said North Korea had shown no interest in dialogue, but the US, South Korea and Japan would continue to coordinate diplomatic strategies towards that end.

"Ultimately, we do hope that Pyongyang will see fit to engage with at least one of us at some point," she told the Hudson Institute think tank.

Yoon's speech came amid a dispute with opposition lawmakers over his appointment of what they view as a pro-Japan, revisionist former professor to oversee a national independence museum, another sign of divisions and political polarisation over Yoon's efforts to boost security ties with Tokyo.

Major independence movement groups which had for decades co-hosted the annual National Liberation Day events with the government held a separate ceremony for the first time in protest, joined by opposition lawmakers.

Yoon's office has said there were "misunderstandings" about the appointment, and was seeking ways to resolve them.

Yoon, in the speech, also raised the idea of launching an international conference on North Korea's human rights and a fund to promote global awareness on the issue, support activist groups, and expand North Koreans' access to outside information.

"If more North Koreans come to recognise that unification through freedom is the only way to improve their lives and are convinced that a unified Republic of Korea will embrace them, they will become strong, friendly forces for a freedom-based unification," he said.

Yang Moo-jin, president of the University of North Korean studies in Seoul, said North Korea could take Seoul's plans to promote human rights and outside information while offering aid and talks as contradictory and a threat to Kim's regime.

"Those plans look good on the surface, but from Pyongyang's perspective, they are nothing but programmes that could contribute to overthrowing the regime," Yang said.

Yoon's speech marked a departure from his focus on Japan during past anniversaries, even as at least three Japanese cabinet ministers visited the controversial Yasukuni shrine which Seoul calls a symbol of the country's wartime aggression.

Seoul's foreign ministry expressed deep disappointment over the visit, urging Tokyo to "face history and demonstrate humble reflection and genuine introspection on the past".

The main opposition Democratic Party denounced Yoon's speech as a plot to consolidate his "pro-Japan, ultra-right forces" and instigate war with North Korea.

Yoon's office said the speech showed Seoul's confidence by seeking cooperation with Tokyo while raising thorny historical issues, as well as laying groundwork for future North Korean unification even without Pyongyang's help.

"We cannot be optimistic about when and how they (the North Koreans) will respond," an official told reporters.

  - Reuters