Five months after the last round of sanctions was approved, three of the five permanent members of the UN Security Council — United States, France and Britain — support such a move, while Russia and China are more hesitant.
With resolutions 1737 (December 2006) and 1747 (March), the Security Council imposed then increased sanctions on Iran for refusing to halt sensitive uranium enrichment activities.
The sanctions aim to convince Tehran to stop enriching uranium and building a heavy-water reactor in Arak, and to cooperate fully with the inspectors from the International Atomic Energy Agency (IAEA).
After vowing that its nuclear program is for peaceful civilian aims, Tehran has not changed its stance and leaders have vowed that nothing will force it to halt uranium enrichment, which can be used to produce nuclear weapons.
Washington fears the program is a cover for nuclear weapons building and, in turn, has pressed for new measures, including via the United Nations.
On Wednesday the United States announced it planned to designate the Iranian Revolutionary Guards as a "terrorist" group, possibly in the coming weeks.
The Guards are an elite force of 100,000 troops whose influence stretches into the fields of business and politics and would be the first national military branch included on the US terror list.
Even though the European Union has no such plans to place the Revolutionary Guards on its terror list, French ambassador to the United Nations Jean-Maurice Ripert told reporters that Paris believes Iran needs to be dealt with "very firmly."
"Unfortunately it appears that the Iranians have still not delivered what the Security Council has asked them to do and we will reach a time when we will have to again boost the international sanctions," he said.
"I am not sure that we have the choice of waiting until October to bring this matter before the Security Council," he added.
At the end of July, British Prime Minister Gordon Brown said "there will probably be a third (UN Security Council) resolution in relation to Iran soon and I believe that that is a way forward that is working and will work."
Brown, who appealed to Iran to "understand the fears that other countries have about the development of a nuclear weapons program," also refused to rule out military action against the Islamic republic.