"This date of October 31 is not a criteria for us, because we have not accepted this resolution," Ali Akbar Salehi said amid a crucial visit to Iran by a team of top IAEA inspectors.
"But we will continue to cooperate with the IAEA and will try to make it so that the answers to outstanding issues will be given as quickly as possible," he added.
In a resolution on September 12, the IAEA's board of governors gave Iran until October 31 to guarantee it was not developing and would not develop atomic weapons under the cover of its civil nuclear programme.
The resolution, passed after heavy US lobbying, also called on it to sign an additional protocol of the UN nuclear Non-Proliferation Treaty (NPT) and implement it immediately and unconditionally.
An IAEA team is currently in the Islamic republic for what the agency's chief Mohamed ElBaradei has described as a "decisive" round of inspections and talks aimed at clearing up a number of key questions -- or "outstanding issues" -- related Iran's nuclear programme.
The US alleges Iran is using a nuclear power programme as a cover for weapons development, a charge Iran has fiercely denied.
But a failure by Teheran to meet the deadline could see it being declared in violation of the NPT and the matter being passed to the UN Security Council, which could in turn decide to sanction Iran.
Although casting aside the deadline -- branded by a string of top officials here as part of a US-Israeli plot to undermine the Islamic regime -- Salahi said Iran was determined to continue its cooperation with the IAEA, further dampening fears that Iran could pull out of the NPT altogether.
"We have accomplished a number of things by going beyond our obligations (under the NPT), and as long as there are outstanding issues, we have promised to continue as before," he said.
And he said the preparatory talks here with the IAEA team -- headed by Pierre Goldschmidt, an IAEA deputy director general who oversees the department of safeguards -- have already resulted in an accord on the "general framework on what needs to be done" over the coming weeks of IAEA scrutiny.
"Up to now, everything is going well," Salahi said, adding the talks were taking place within a "logic of dialogue".
However the representative refused to be drawn on the debate surrounding the demands that Iran sign the additional protocol to the NPT which would allow the IAEA to conduct surprise visits to suspect sites rather than the pre-arranged tours they conduct now.
"That is another question," Salahi said. "We have not discussed the additional protocol."
On Saturday, Intelligence Minister Ali Yunessi said Iran would sign the protocol under certain conditions.
Yunessi said Iran, as a member of the IAEA, ought to have the same technological assistance with its nuclear programme as is given to other states, but that this aid had been denied because of "American pressure."
Only Russia is aiding Iran's civil nuclear programme, an assistance that Washington is trying to see ended.
And highly influential former president Ali Akbar Hashemi Rafsanjani posed four conditions Friday on signing the additional protocol, including no inspections in non-nuclear military sites and places of worship.