Delays in granting a former jihadist an entertainment visa for Hobart's Dark Mofo festival could be seen as an attack on free speech, according to Australian journalist Peter Greste.
Mr Greste, who was imprisoned in Egypt in 2013, is due to interview British scholar Muhammad Manwar Ali as part of the Dark and Dangerous Thoughts event this weekend.
As the keynote speaker, Mr Ali applied for an entertainment visa in April and is scheduled to fly into Hobart on Friday.
Organisers said the Department of Home Affairs told them last week his visa would take "many months" to process.
The event will go ahead as scheduled but with Mr Ali appearing via satellite link.