A new round of stricter architectural rules may slow construction permit applications, further damaging a building sector already buffeted by tougher regulations, slowing demand and soaring bankruptcies, according to Haseko Corp.

The new rules, which go into effect Friday, require that holders of two new types of architecture licenses check blueprints for buildings larger than a certain size to verify structural integrity before a construction permit can be granted.

The stricter regulations pose a risk of delays in filing applications, said Hidetake Ishinaga, a spokesman at Tokyo-based Haseko, Japan's largest condominium builder. The company is encouraging its employees to take the new exams and is streamlining the way it designs structures, he said.

The requirements are the latest steps to tighten regulations since the 2005 discovery that architect Hidetsugu Aneha falsified earthquake resistance data for hotels and condominiums he designed. Changes to the building code in June 2007 quadrupled the time needed to screen applications, helping to spark the biggest decline in housing starts in 40 years, according to the Land, Infrastructure, Transport and Tourism Ministry.

As many as 30,000 construction permits a year may have to be vetted by holders of the first-class architectural license in structural design, one of the new specializations, officials at the land ministry said.

In tests held in June and July, 5,983 people obtained the structural design license and 2,319 became holders of the first-class license for designing buildings, the ministry said.

Twenty-one of 28 bankruptcies by listed companies this year were in the property sector, as banks cut off lending and housing demand slowed. New condominium offerings in the Tokyo area fell for the 14th straight month in October, the longest slide since the bursting of the economic bubble.