"The situation has deteriorated over the past six months and we have already heard of several cases of such attacks, which are mainly staged by radical Muslims," Martens said.
He added that these incidents, as a rule, pertain to household-related issues.
"In some refugee centers, for example, Christian migrants are banned from going to the kitchen because they are seen by Muslim migrants as kafirs (infidels) who allegedly can desecrate cookware," Martens said.
This is something that also explains Muslim families forbidding their children from play with Christian kids, according to Martens.
"The number of cases related to negative attitude toward Christian refugees has showed no sign of abating in recent weeks," he said.
More than 1.1 million migrants and refugees arrived in Germany in 2015. Chancellor Angela Merkel's government came under pressure over its open-door policy after a series of attacks on women in Cologne, allegedly by men from refugee backgrounds.