Japanese Prime Minister Shinzo Abe said Wednesday that the alliance between Seoul, Washington and Tokyo should be strengthened in the face of North Korea's latest nuclear test.

"North Korea's nuclear test will never be allowed as it is a grave threat to Japan and South Korea in terms of national security," Abe said during a meeting with South Korean lawmakers in Tokyo.

Pyongyang asserted on Jan. 6 that it has successfully tested a hydrogen bomb, a claim disputed by outside experts but that still raises concerns about the North's advances in weapons technology.

"Cooperation between Japan, South Korea, and the United States is becoming more important in a situation like this," Abe said, asking the South Korean lawmakers to act as a bridge between the two countries.

A South Korean parliamentary delegation led by a confidant of President Park Geun-hye visited Tokyo for the meeting with Abe.

It marks the second visit by the bipartisan group headed by Rep. Suh Chung-won, a seven-term lawmaker of the ruling Saenuri Party with reportedly close ties to Park.

The one-day visit by members of the South Korea-Japan lawmakers' association comes after two countries agreed to resolve the issue of Tokyo's sexual slavery of Korean women during World War II.

Abe said the issue of sexual slavery was solved finally and irreversibly through his phone call meeting with President Park Geun-hye and the meeting of the two countries' foreign ministers.

The delegation includes Reps Kim Tae-hwan, Shim Yoo-joe and Joo Ho-young of the Saenuri Party, as well as Kim Sung-gon of the main opposition Minjoo Party of Korea. (Yonhap)