Iran's Guardian Council ratified a bill on Wednesday approving the nuclear deal reached by Tehran and six world powers, state news agency IRNA and other agencies said, allowing the government to implement the agreement.

Parliament on Tuesday approved the bill with a strong majority, in a victory for President Hassan Rouhani's government over conservative opponents of the July 14 deal, known as the Joint Comprehensive Plan of Action.

The Guardian Council, made up of six Muslim clerics appointed by the Supreme Leader and six lawyers elected by parliament, is charged with ensuring draft laws do not contradict religious laws or Iran's constitution.

"The majority of the Guardian Council did not find the bill... to be against religious law and the constitution," the council's spokesman Nejatollah Ebrahimian was quoted as saying by the Fars news agency.

The exact stance of Supreme Leader Ayatollah Ali Khamenei, who has the last word on all matters of state, is not known.

To date, he has neither approved nor rejected the agreement, but has commended the work of Rouhani's negotiating team.

Provided Khamenei does not openly oppose the bill, analysts expect Iran to begin shutting down parts of its nuclear program in the coming weeks. When completed, that process will result in most international sanctions, imposed on Iran since 2006 over concerns it was covertly seeking atomic bombs, being lifted.