Office vacancy rates rose to record highs in both Tokyo and Osaka last month after the March 11 disaster, according to Miki Shoji Co.

Unoccupied office units in Tokyo rose to 9.19 percent in March from 9.1 percent a month earlier, while the vacancy rate in Osaka gained to 12.4 percent from 12 percent in February. Both rates were the highest since Miki Shoji started compiling data in 1990.

Occupancy rates in Osaka may pick up in the coming months as Japanese companies rethink their century-long trend of concentrating resources in Tokyo and residents flee in the wake of the disaster and amid the Fukushima nuclear plant crisis.

Servcorp Ltd., an office-leasing and management firm, and recruiter Robert Walters PLC see business picking up in Osaka.

"Going forward, the focus will be on the movement by tenants that have offices in Tokyo after the earthquake," Miki Shoji said in the report released Thursday.