The company's Sendai Technology Center in the city of Tagajo is the only Sony plant still offline after a powerful earthquake and tsunami hit eastern Japan on March 11. Numerous factories of major electronics makers were halted after the quake but few were directly hit by the tsunami like the Sony plant was.

It was inundated with about 1.5 meters of water, mud and debris that caused heavy damage to the first floor of the building. A visit to the factory in late March found workers clearing out mud and crushed cars from the facility. That work has continued and now Sony is anticipating the restart of some operations.

The factory is Sony's principle production base for professional video tapes, blank Blu-ray Discs and other media products, and the halt in production caused a pinch on supply of some professional media products like HDCAM video tapes for portable TV cameras.

While the optical disc production will start in late May, production of magnetic tapes, such as those for TV cameras, isn't likely to resume until late July.

Sony said it plans to move production of other products and components previously manufactured in Tagajo to other factories to speed resumption of their production.