David Byle, 46, was taken into custody on April 6 after applying for a residency permit, the Morning Star News reported.
He's now in a holding centre for people awaiting deportation.
It's claimed the Turkish Ministry of the Interior want him to be deported but it's unclear on what grounds they think he is a "danger to public order".
Byle is known for his evangelising and was due to teach a group of Turks techniques for spreading the Gospel days before his arrest.
He is a ministry leader at U.S.-based International Christian Response, which works with persecuted Christians.
He has been arrested in Turkey before, in April 2007 he was questioned after being accused of 'aggressive evangelism' in Istanbul.