Protesters will call for Steve Kaczynski to be released from prison without charge when they gather outside the Turkish Consulate tomorrow.
Mr Kaczynski was arrested in April when police raided the Idil culture centre in Istanbul ahead of a symposium where he was due to act as interpreter.
It is understood he is being held on suspicion of being a member of banned left-wing organisation DHKP-C.
He began his hunger strike on June 25 in protest at being locked up in isolation for 23 hours a day and denied access to books and letters.
His family fear it could be more than a year before a date is set for his trial.
Tomorrow’s protest will be held outside the Turkish Consulate on George Street at 2.30pm.