Gulf Air has pushed back its planned resumption of flights to Iran until early 2013, saying the Iranian civil aviation authority has yet to approve the airline's new flight schedule.
The Bahraini flag carrier says in a statement: "Gulf Air regrets to announce its services between Bahrain and Iran have been deferred until further notice.
"The national carrier apologises to those passengers affected and reassures them that it is working hard to get approval from the relevant authorities to re-launch services as soon as possible."
Gulf Air had expected to resume flying to Tehran, Mashhad, Shiraz and Isfahan gradually from 28 October, having received approval from the Bahraini authorities to re-enter the country.
All of its services to Iran, Iraq and Lebanon were suspended in March 2011 amid concerns that Shi'ite groups overseas were seeking to enflame civil unrest within the tiny Gulf kingdom.
Flights to Lebanon were restored in June 2011, while Iraqi services got underway last month with the resumption of the Bahrain-Najaf route.