Following major pressure from the IAEA and the international community, Iran signed the additional protocol to the Non-Proliferation Treaty (NPT) in December last year but has so far held back its ratification.
The additional protocol gives IAEA inspectors increased powers in their investigation into Iran's bid to generate nuclear energy, seen by many as a convenient cover for nuclear weapons development.
The deputy head of the Iranian parliament's influential Foreign Policy and National Security Commission, Mohamoud Mohammadi, said the ratification of the text was "conditional to the IAEA approving our use of nuclear technology for peaceful purposes."
"The majority of my colleagues in the parliament think this way," he added, when asked if this meant Iran was waiting to be given the all-clear by the IAEA and have its dossier been taken off the top of the Vienna-based body's agenda.
"The fear is that the additional protocol could be used as a tool for political pressure. If they treat our dossier in a purely technical fashion, then we will cooperate," he said in an interview.
Pending ratification of the text, Iran has nevertheless pledged to accept a reinforced inspections regime that includes short-notice visits to suspect nuclear facilities.
But the IAEA wants the text to be ratified as a "confidence-building gesture" as soon as possible.
The next IAEA meeting on Iran is in September, when Iran is hoping it will be cleared. But the diplomats say that is unlikely, pointing to Iran's failure so far to fully answer a number of outstanding issues.
The United States, which asserts Iran is already in violation of the NPT, wants the matter referred to the UN Security Council for possible sanctions.
Speaking late Tuesday, Mohammadi repeated denials that Iran was seeking nuclear weapons -- but he did acknowledge that some officials in Iran were in favour of acquiring a nuclear deterrent.
"There is one view in Iran that we are living in an atomic-infested area. I firmly believe atomic energy can have dual usage. But the policy is set by the Supreme Leader (Ayatollah Ali Khamenei), who treats this from the point of view of Islam," he said.
"And the view is that the destructive part of nuclear technology is haram (forbidden), just like alcohol or murder."
Mohammadi also said he was not alarmed by speculation that regional arch-enemy Israel could conduct military strikes against Iranian nuclear facilities.
"We don't consider their threats to be serious, because they know that any action against our national interests will be met with a decisive response," he said.
"In order for Israel to continue existing, it should learn to coexist with its neighbours."
But the deputy, a former foreign ministry spokesman and ambassador, also asserted that Iran's official policy was not for the destruction of the Jewish state and signalled Iran would not be opposed to a two-state solution in the event of a viable peace accord.
"(The destruction of Israel) is not an official policy. It is thought, a response to racism, occupation and repression. You can compare it to the attitude people had towards the apartheid regime in South Africa," he said.
When asked if Iran would accept Israel's right to exist if a peace accord that satisfied the Palestinians' elected leadership was stuck, he said the Islamic republic would reassess its position.
"If that hypothesis materialised, Iran would adopt new policies. It would assess any new situation. What is important is that Palestinian rights are respected. Until that time we will never respect an occupier," he said.