Mr Mottaki said China would possibly sell enriched uranium to Iran
Iran has said it may agree to send some of its existing stock of low-enriched uranium abroad for further processing.
Foreign Minister Manouchehr Mottaki's comments are the first official sign Iran could accept parts of a UN proposal for its nuclear programme.
Under the draft UN plan, Iran would send its enriched uranium to Russia and France to be turned into fuel.
Mr Mottaki told state media Tehran was considering whether to buy enriched uranium instead, but would decide soon.
He told Iran's Irna news agency there were two options available to Tehran: "Either to buy it [enriched uranium] or to give part of our fuel for further processing abroad."
He named China as a possible provider of such fuel, saying if it was interested, "Iran will welcome China's participation".
"Iran's decision on the provision of necessary fuel for the Tehran reactor will be announced in the next few days," he said.
The Iranian government had promised to respond this week to the UN proposal, after missing Friday's deadline to do so.
NUCLEAR FUEL CYCLE
Mined uranium ore is purified and reconstituted into solid form known as yellowcake
Yellowcake is converted into a gas by heating it to about 64C (147F)
Gas is fed through centrifuges, where its isotopes separate and process is repeated until uranium is enriched
Low-level enriched uranium is used for nuclear fuel
Highly enriched uranium can be used in nuclear weapons
Under the plan - which emerged from talks in Vienna between the UN nuclear watchdog, Iran, France, Russia and the US - Tehran would send its enriched uranium to Russia and France, where it would be further enriched.
The proposed deal is seen as a way for Tehran to get the fuel it needs for an existing reactor, while giving guarantees to the West that its enriched uranium will not be used for nuclear weapons.
All the other countries involved have already confirmed their support.
Opposition inside Iran to the agreement is said to be growing and the BBC's Tehran correspondent, Jon Leyne, says that if the government rejects the proposal, it will put the whole future of the nuclear negotiations in doubt.
On Sunday, a team from the UN watchdog, the International Atomic Energy Agency (IAEA) began an inspection of an Iranian uranium plant.
The Fordo plant, built into a mountainside near the city of Qom, was previously secret.
Its existence was announced by the Iranian authorities last month, apparently because Western intelligence agencies had already discovered it, says our correspondent.
Iran agreed to open the site to monitoring at talks with the five permanent members of the UN Security Council plus Germany in Geneva on 1 October.
The inspectors are not expected to report until they leave Iran, but some Iranian officials have already said the inspection shows their country's nuclear activities are both transparent and peaceful.
Iran says its nuclear programme is for purely peaceful purposes, but the revelation of the existence of the new plant increased fears in the West about Tehran's intentions.