Unilateral sanctions will not help resolve issues on the Korean Peninsula, Chinese Foreign Minister Wang Yi told his Japanese counterpart over the phone in the aftermath of a fresh round of nuclear testing in North Korea last week.

The call also came after the U.S. State Department's special representative for North Korea met Japanese officials on Sunday and said the U.S. may launch unilateral sanctions against the reclusive state.

China is North Korea's most important ally and has come under intense criticism for not doing enough to curb Pyongyang's nuclear ambitions.

In the call on Wednesday, Wang said China opposed "unhelpful" unilateral sanctions on North Korea even as he reiterated China's opposition to Pyongyang's nuclear testing. The East Asian giant was willing to work with other permanent members of United Nations Security Council to formulate a "necessarily response" to new developments on the Korean Peninsula, he added.