Iran says its nuclear programme is for civilian purposes
China's ambassador to the United Nations, Zhang Yesui, has said the time is not right to consider more sanctions against Iran.
The UN Security Council, including China, has previously called for Iran to stop enriching uranium and has issued three sets of sanctions.
Iran's leaders insist their atomic programme is only meant for energy-generating purposes.
But the US and its allies fear Iran is trying to develop nuclear weapons.
China has the presidency of the UN Security Council during January, and is one of its five permanent veto-holders.
Mr Zhang told reporters at the UN that "more time and patience" was needed to find a diplomatic solution to the impasse.
The Chinese ambassador's comments come days after after Iran missed an end-of-year deadline set by the US to respond positively to offers of talks about its uranium enrichment programme.
Plans on how to respond are apparently still up in the air, says the BBC's Tom Lane, at the UN in New York.
Diplomats at the UN say senior figures from Europe, the US, Russia and China will meet later this month to exchange opinions, our correspondent says.
US officials have previously called for "crippling" sanctions in the event of a diplomatic failure.
However, recent reports suggest they are currently thinking of "targeted sanctions" that focus on people and companies involved in Iran's nuclear programme, our correspondent adds.
Analysts say it could take Iran from between 18 months and three years to build a nuclear bomb.
With all this in the background, diplomats say it could be many weeks and even months before a deal is reached at the UN, our correspondent reports.
However, it is possible the US and its allies could roll out new sanctions of their own sooner.