BEIJING (Reuters) - China is willing to promote dialogue between North and South Korea as stability on the Korean peninsula is also in China's interests, President Xi Jinping told his South Korean counterpart on Wednesday, China's Foreign Ministry said.

Beijing is Pyongyang's sole diplomatic and economic ally, but relations have been strained by North Korea's bellicose actions, including carrying out a third nuclear test last month.

"Peace and stability on the Korean peninsula is in the vital interests of the people of the peninsula and also of the Chinese people," Xi told President Park Geun-hye in a telephone call, the Foreign Ministry said in a statement.

"China is committed to maintaining peace and stability on the peninsula and realizing the peninsula's denuclearization, and upholds resolving the issue through dialogue and consultation," Xi added.

"China is willing to provide necessary help to promote reconciliation and cooperation."

Beijing joined a new round of U.N. sanctions against North Korea this month and has said it wanted them implemented.

But questions remain over how closely it imposes restraints on its neighbor, viewed as both an embarrassment and a strategic bulwark against U.S. influence in the region.

(Reporting by Ben Blanchard, Huang Yan and Sui-Lee Wee. Editing by Dean Yates)