The World Evangelical Alliance (WEA) has asked Turkey to review the expulsion of dozens of foreign Christians.
In a statement to the 45th session of the United Nations Human Rights Council, the WEA said 60 Protestant church members had been expelled or banned from Turkey.
The WEA said that the incidents had all occurred within the past two years, leading to the Christians being "denied residency, arbitrarily and without due process", Evangelical Focus reports.
The WEA statement highlights the case of David Kandasamy, a Sri Lankan national who lived in Turkey for 20 years before being barred from re-entry.
According to the WEA, he is married to a Turkish Christian, with whom he has four children who are all Turkish nationals.
In another case, Andy and Cathryn Hoard were banned from re-entering the country after a short trip away. The couple had lived in Turkey for 30 years.
The WEA says Mrs Hoard "spent three days detained in a windowless immigration holding cell before being deported to the United Kingdom".
"Spouses have been separated from their families. Expats were denied access to their property and investments that had previously been carefully investigated by Turkish authorities and received their full approval," the WEA said.
"The authorities have given no explanation apart from telling these Christians that they constitute a threat to national security according to confidential government reports.
"Turkish authorities have denied the lawyers of these expats access to the confidential reports, and therefore, the authorities have offered no possibility for a fair and just appeal to review these orders in accordance with international law, namely article 13 of the ICCPR."
It concluded with a call for "a fair and just recourse against national security decisions and for the examination of the facts behind such decisions".