The Diet enacted four construction-related laws Wednesday in response to the building scandal involving fake earthquake-safety data that has rocked the nation since November.
The four bills were passed by the Upper House. They cleared the Lower House on May 25. The laws take effect within a year.
The package includes a revision to the Building Standards Law, which features a provision to toughen the maximum penalty for architects and builders who have erected unsafe buildings.
The scandal broke in November when the Land, Infrastructure and Transport Ministry announced that 20 condo complexes and a hotel may lack the strength to resist strong quakes because architect Hidetsugu Aneha falsified quake-resistance data.
The ministry says the now-disqualified architect had been involved in the structural design of numerous condo complexes and hotels found to be vulnerable to a major quake.
Aneha was arrested April 26 and charged May 17 with allowing an architectural designer to use his name as a licensed architect.
Numerous inspection agencies and municipalities overlooked the faked data for several Aneha-designed buildings.
In response, the revised Building Standards Law introduces a system in which inspection organizations facing certification by prefectural governments will have to recheck statements on quake-resistance data for reinforced concrete buildings taller than 20 meters and wooden buildings taller than 13 meters.
Under the current Building Standards Law, the heaviest penalty for constructing an unsafe building is a 500,000 yen fine with no prison term.
The revised law increases the fine to up to 3 million yen and includes a maximum prison term of three years.