Rafsanjani's comments came after Joe Biden, the US vice-president, said that Washington is open to negotiations with Tehran if it abandons its nuclear programme.
"We will be willing to talk to Iran, and to offer a very clear choice: continue down the current course and there will be continued pressure and isolation; abandon the illicit nuclear programme and your support for terrorism and there will be meaningful incentives," Biden told a security conference in Munich on Saturday.
The US and other Western powers say that Tehran's uranium enrichment programme is focused towards the manufacture of a nuclear weapon.
Iran, for its part, says that it is not trying to build such a weapon and that its nuclear work is aimed at generating electricity.
"We have explicitly announced that there is no nuclear weapons program in our agenda and we are ready to negotiate wherever necessary and allow them to supervise our activities," Rafsanjani said.
"We have signed the nuclear Non Proliferation Treaty and we practically implemented its additional protocol although we hadn't signed it. I think that they're making a pretext out of the nuclear issue."
Also speaking on Monday, Ali Larijani, Iran's parliamentary speaker, said that the US's apparent policy shift towards his country's government is positive.
"Larijani recognised that Biden's speech and his support for multilateralism seemed to be very positive," a Spanish government spokeswoman said after Larijani held talks with Jose Luis Rodriguez Zapatero, Spain's prime minister, in Madrid.
Larijani, a former nuclear negotiator, told Zapatero that Biden's comments in Munich marked "an important change in US foreign policy," the spokeswoman said.