The proposals are reported to include a travel ban on some officials, an expanded list of people and companies subject to an asset freeze, an arms embargo, and financial and trade restrictions.
After talks on March 9, China's UN Ambassador Wang Guangya said Beijing was concerned that proposed financial and trade sanctions would not specifically target Iran's nuclear sector but could result in punishing the Iranian people.
Wang said Russia had difficulties with proposals for sanctions targeting entities controlled by Iran's Revolutionary Guards, which the ambassador described as an "institution."
The possible new sanctions are being debated by the Security Council following Iran's refusal to suspend uranium enrichment, as demanded by a Security Council resolution in December.
In addition to Russia and China, possible sanctions are being debated by the United States, France, Britain, and Germany.
(compiled from agency reports)