The organisation, which supports believers around the world who are under pressure for their faith, said "we are seeing very clear restrictions in Europe", highlighting recent terror attacks in France and other countries.
Speaking at the Houses of Parliament on Wednesday evening, CEO Lisa Pearce, said: "It's not entirely unthinkable. I think, a few years ago, that wouldn't have been seen as possible."
Lisa Pearce was answering a question from Premier at an event marking the release of its World Watch List 2017, a list of 50 nations around the globe where oppression encountered by Christians is worst.
The list, which ranked North Korea the worst country for Christian persecution, was described as "deeply worrying" by Conservative politician Theresa Villiers who also spoke at the event.
#NorthKorea again tops @OpenDoorsUK list of nations where persecution of Christians is worst. Report from Parliament for @PremierRadio pic.twitter.com/jVQx5WHAbq
— Alex Williams (@AlexWpremier) January 11, 2017
She alluded to incidents including the murder of Fr Jacque Hamel at a church in Normandy in July 2016 by two men pledging allegiance to Islamic State (IS), and the IS truck attack on a Christmas market in Berlin which left twelve people dead.
Lisa Pearce said Open Doors researchers gathered hundreds of reports at refugee camps in Germany of Christians, who had fled countries like Iraq and Syria, being physically and sexually assaulted.
She went on to say: "Ten years ago, the geography of persecution was very clear.
"As an organisation, we would look at the countries within which it was hardest to be a Christian. We would focus very much around countries.
"Now, we're having to focus more around people groups because people are on the move.
"People are migrating and moving and, therefore, the geographies where people experience persecution are really much less clearly demarcated."