A nun in Nebraska who teaches in a secondary school has been told that she is not allowed to wear her habit in the classroom.

37-year-old, Sister Madeleine Miller, was shocked to learn that, under a little-known law nearly a century old, habits were banned.

The vaguely worded ban prohibits teachers from wearing any sort of religious clothing, from burqas to yarmulkes.

"I could have been arrested, jailed, fined or had my license taken away if I had tried to teach," Miller said on Tuesday.

Now, state lawmakers are looking to end the ban, which was passed in 1919 under pressure from the Ku Klux Klan amid a national wave of anti-Catholic sentiment.