The Buildings Department has found a 540-square foot basement along with some other illegal structures at the homes of the new Justice Secretary Teresa Cheng and her husband.
Department officials inspected her home and her husband's home – which is the adjacent building – on Tuesday morning.
A department spokesman said they found illegally built structures in both houses in Tuen Mun.
He said they found a rooftop glasshouse, an extended wall on the ground floor, and a 50 square-metre basement in Cheng's house.
The officials also found a rooftop glass house, a two storey-high extended wall, a 50 square metre basement and a garden pond that were illegally built at Cheng's husband's house.
The spokesman also said the department had never received any request to change the structure of Cheng's house in the past.
The department said it received a media enquiry about Cheng's house in late December and made a preliminary inspection last Friday. It said it will follow up on the matter according to the law.
Meanwhile, Housing Secretary Frank Chan has admitted that he has visited Cheng's husband's house several times, but said he did not notice any unauthorised structures.
The minister has a close relationship with the couple, and acted as a witness for the marriage between Cheng and her husband, top engineer Otto Poon.