UN ambassadors from the United States, Britain and France are expected to introduce a resolution this week to legally oblige Iran to comply with UN Security Council demands that it halt all uranium enrichment work.
But Manouchehr Mottaki told the Kayhan newspaper on Tuesday: "The thing these two countries [China and Russia] have officially told us and expressed in diplomatic negotiations is their opposition to sanctions and military attacks.
"At the current juncture, I personally believe no sanctions or anything like that will be on the agenda of the Security Council," he said.
Western diplomats say China and Russia - both veto-wielding permanent members of the council, will probably back a UN resolution demanding a halt to Iran's nuclear fuel work, but are not yet ready to back sanctions.
Iran has been referred to the UN Security Council after failing to convince the International Atomic Energy Agency that its nuclear power station programme is not a front for building an atom bomb.
The head of Iran's atomic energy agency also said Iran had enriched uranium to 4.8% but would not enrich above 5%, keeping the country's enrichment work within a range used for nuclear power stations.
Experts said uranium enriched to a range of 3% to 5% is a low level used in atomic power reactors. Uranium would have to be enriched far higher, to 80% or more, to make nuclear weapons, which is what the West fears Iran wants.
Iran said at the end of April it had enriched uranium to more than 4%. Prior to that, it had told the UN nuclear watchdog that it had enriched to 3.6%, a level confirmed by the IAEA.