Virtual Private Networks have also stopped functioning and internet users are facing serious problems accessing social networks and certain websites.
Critics have accused paranoid mullahs of desperately try to prevent anyone using the net to organise protests and demonstrations during the June presidential ballot.
But despite a massive cutback in bandwidth across the regime, telecommunications chiefs have insisted there are ‘no problems’ with online activity.
The director of the public relation at Iran Telecommunications – which provides infrastructures to supply bandwidth to ISPs – blamed Tehran Communication for any loss of the Internet.
And Internet Supreme Council member Alireza Shahmirzaii described reports of recent Internet slowdowns as ‘just an illusion by some who are trying to spread rumours during the election’.
He told the Tasnim news agency last week: “We hadn’t had any failures in the bandwidth causing problems with information exchange.
“There aren’t any problems in Internet communications and people have access to every permitted website.”