A body tasked with policing the Internet laid down a two-month deadline Tuesday for Iran's government to regularise the use of Instagram or access to the site would be blocked.
Iranian authorities regularly block Twitter, Facebook and other social networking sites considered damaging to the values of the Islamic republic.
Mohammad Ali Asfani, a member of the Iranian committee for filtering the web, said the two months would allow authorities to contact Instagram over secure access to its contents.
"If this is done, we will not filter Instagram," he said, quoted by ISNA news agency.
Last month, Iran blocked access to an Instagram page devoted to the lifestyle of Tehran's young elite that stirred indignation in the sanctions-hit country.
And in September, the judiciary gave the government a month to ban the messaging applications Viber, Tango and WhatsApp over insults of Iranian officials, but they remain accessible.
President Hassan Rouhani, a moderate, has pledged an easing of Internet censorship, while several members of his government have Facebook and Twitter accounts.
But ultra-conservatives who control key institutions are opposed.