"We can really contribute to the political dialogue between the parties concerned, especially between the United States and DPRK," or North Korea, he added.
Asked when the council might next vote on the draft resolution, Zhang said only that consultations were continuing.
When Pyongyang announced the end of its moratorium on Wednesday, the US response was cautiously worded. Secretary of State Mike Pompeo urged the North's leader Kim Jong Un to "take a different course" and stressed that Washington wanted "peace, not confrontation."
But the US gave no suggestion it was ready to ease sanctions. Similarly, European diplomats have insisted for months that there should be no lifting of the sanctions until the North takes concrete and verifiable steps toward nuclear disarmament - which is the US goal as well.
The Chinese-Russian draft, distributed to other council members on December 17, calls for an end to several sanctions agreed in 2017, notably a ban on purchasing textile and seafood products from North Korea. Beijing and Moscow are also calling for an end to a measure that required UN member states to stop employing North Korean workers, a major source of income for Pyongyang, by December 22, 2019. Asked whether China - the largest foreign employer of North Korean workers along with Russia - had complied with that requirement, Zhang said his country had taken the sanctions "seriously." He added, however, that "we do see some negative effects by the sanctions, especially sanctions affecting the livelihood of innocent, ordinary people. "We should adjust the sanctions," he added, to alleviate "the sufferings of innocent peoples."
North Korea's self-imposed testing ban had been a centerpiece of its roller-coaster nuclear diplomacy with the US over the past two years.
Any actual test would likely infuriate US President Trump - who is also facing sharp tensions with Iran and his still-unscheduled impeachment trial.
The Security Council's rotating presidency is held this month by Vietnam, one of five new non-permanent members to begin two-year terms on the council on January 1. The others are Tunisia, Niger, Estonia and Saint Vincent and the Grenadines.