Authorities in Shenzhen, Guangdong province, recently discovered an illegal structure on the roof of a luxury high-rise, Yangcheng Evening News reported on Tuesday.

The templelike structure was built on the roof of a 21-story residential building in the city's Nanshan district years ago. A thick metal door with a fingerprint lock separates the 21st story from the roof.

Liu Minxing, deputy head of the law enforcement team of the Shahe subdistrict office, said that after receiving the report of the illegal structure, his team went to the building several times, but couldn't check out the rooftop structure because they could not gain access to it.

The structure's owner refused to open the door and did not meet the team, Liu said.

But Liu said that the on-roof structure is illegal because the law bans such structures from being built on roofs.

Some people in the building said that the owner of the structure often held sacrifices in it, and ash of burned paper fell to the windows of their apartments.

The owner of the rooftop structure is the owner of the apartments on the 21st floor, but the residential management office declined to provide any information about the owner, citing privacy concerns.

According to a broker with a real estate agency nearby, the price of the building's apartments averages 30,000 yuan ($4,900) per square meter, and the total price of the 21st-floor apartments was over 15 million yuan.

"The owner of the apartments on the 21st floor who built the rooftop structure must be rich or a high-ranking official who had a lot of connections to avoid punishment," the broker said.

Liu said his team will continue their investigation into the structure and try to get information about the owner from the residential management office.

"If the owner refuses to co-operate with our investigation, we will connect with police, firefighters and the local safety supervision department to form a working group and find a way to open the door," Liu said.

The owner could be punished under the law concerned if the structure is deemed to be illegal, Liu said.