A luxury hotel in South Korea is apologizing after guests discovered that an issue with the mirrored windows allowed outside observers to see into the women's sauna area.

The Grand Josun, a recently-opened five-star resort on the island of Jeju, said the mirrored windows in the sauna area are designed to prevent anyone outside the property from seeing in during the day, and blinds are supposed to come down at dusk, when the mirrored effect no longer works.

Guests complained online recently that they discovered the sauna area was sometimes visible from outside the building. They said they could see the sauna, bathroom and showers through the windows.

The hotel apologized and said the sauna has been temporarily closed while officials investigate the malfunction with the mirrored windows and blinds.

"We're deeply sorry for causing any inconveniences to our customers in using some facilities at the women's sauna at the Grand Josun Jeju Hill suite for missing mirror coating for some windows and [problems in] operating the blinds," the hotel said in a statement on its website. "The sauna's operation has been suspended and we're closely checking deficiencies and taking immediate action to correct them."

Police said they are reviewing CCTV footage from outside the hotel to ensure no illicit photos or videos were taken.