Lawmakers have been grilling Hong Kong's new justice secretary over a controversy surrounding illegal additions to her home that has highlighted concerns about rule of law in the semiautonomous Chinese city.

Teresa Cheng faced intense questioning in the legislature on Monday about the scandal as well as a separate controversy involving the government's disqualification of a young pro-democracy activist from an upcoming election.

The 59-year-old Cheng, a veteran arbitrator, was tapped to be the city's top law enforcement officer less than four weeks ago.

The same day, local media reports revealed that her suburban mansion was riddled with unauthorized structures.

Cheng, who has refused to step down and denies she lacks integrity, becomes the latest senior government official to be dogged by a property-related scandal.