Rehabilitation of the Wiss Building at 665-667 Broad St. is underway, the J.I. Kislak Organization, managing agent, announced today. The firm is directing the program of repairs for modernizing the 10-story landmark.

Samuel S. Saiber and David J. Schapira, counsel for the owner. Broad Street Investors Co., said that two downtown banks are providing financing. The Bank of Commerce is providing interim financing during reconstruction and the United States Saving Bank will provide permanent mortgage financing of $275,000.

Modernization of the entrance, lobby, hallways, elevators and lavatories will cost $150,000 in the initial stage. This will include virtual replacement of the electrical system required for air-conditioning and other modern appliances.