South Korean President Yoon Suk Yeol asked Chinese Premier Li Qiang on Thursday if Beijing could do more as a UN Security Council member to address North Korea's nuclear threat.
Yoon told Li China should do more to "fulfil its responsibility and role as a permanent member of the UN Security Council" and stressed that Seoul's ties with Washington and Tokyo would only strengthen to counter North Korea, a statement from South Korea's Presidential office showed.
Yoon met Li on the sidelines of an Asean summit in Jakarta.
Li, for his part, reiterated China's support for both sides on the Korean peninsula to advance reconciliation and cooperation.
"China has always advocated maintaining peace and stability on the peninsula and will continue to promote peace talks," China's foreign ministry quoted Li as saying in his meeting with Yoon.
Since 2006, North Korea has been under UN sanctions over its ballistic missile and nuclear weapons tests, but there are aid exemptions.
Hours earlier, Yoon said North Korea's nuclear programme was a threat to all countries participating at the East Asia Summit, and stressed that UN member states should follow the Security Council's resolutions.
The East Asia Summit includes the Asean bloc, China, Japan, the US and others.
"The responsibility is heavier for the permanent members of the UN Security Council who actually adopted the resolutions," he said.
For the past several years, the UN Security Council has been divided over how to deal with North Korea. Russia and China have said more sanctions will not help and want such measures to be eased.
Yoon's remarks come amid reports North Korean leader Kim Jong Un plans to travel to Russia this month to meet President Vladimir Putin and discuss weapons supplies to Moscow.
The US has said North Korea would pay a price for supplying Russia with weapons to use in Ukraine. South Korea has said the UN member states should not violate sanctions, including through arms deals.
Yoon's meeting with Li came after the South Korean leader called for a rules-based maritime order in the South China Sea and as he vowed to enhance cooperation with China and Japan.
In an interview with Indonesia's Kompas newspaper published on Tuesday, Yoon said it was time to put relations among the three Asian countries "back on track".
Yoon said any attempts to change the status quo by force in the South China Seacould not be tolerated.
China claims most of the energy-rich waters but neighbours Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims.
"We need to establish a rules-based maritime order in the South China Sea, a key sea lane in the region, for the Indo-Pacific region to continue prospering, with Asean playing a pivotal role for growth," Yoon said.