So far this year, roughly half of converts to Christianity in Vienna have been Muslim, according to reports.

About half of the 83 adults to have been approved for baptism in Vienna are Muslims, mostly from Iraq, Syria and Afghanistan, according to Friederike Dostal of the Austrian Bishops' conference, Austrian website Kurier reports.

This has increased from one third in 2015.

While the number of refugees in the country will have impacted the figures this year, the preparation time for baptism is one year, so the numbers are expected to be higher in 2017.

The Archdiocese in Vienna is currently handling between five and 10 baptism requests by adults per week.

It's not a descision that will be taken lightly. A conversion from Islam to Christianity can have serious implications.

"This could be my death sentence," said Christoph, an elderly refugee from Afghanistan who has lived in Vienna since 2012.

Speaking to Kurier, he wore dark sunglasses and only used his Christian name to avoid recognition, both for his sake and for his family's, who remain in Afghanistan.

Describing his conversion, he said: "A friend brought me a Bible from Pakistan. I read it in secret, only at home. But I read it every day."

Secrecy is crucial in Afghanistan, he said, as "whoever converts is killed". He was tortured by the Taliban before he escaped the country.

Now in Vienna, he said he feels less safe because of the influx of refugees.

"In Austria, it was once very safe for converts, that has changed due to the strong migration movement," he said.

"The refugee quarters can be dangerous, which deters many from them."

Despite the dangers, he said: "Christianity is the true religion, there is no turning back for me."