Toyota Motor Corp <7203.T> and Honda Motor Co <7267.T> saw their global production slump to around half of year-ago levels in April after the March 11 earthquake and tsunami wreaked havoc with their supply chains.
The drop, flagged by sales figures released at the start of the month, underlines the severity of the parts shortage that is helping overseas rivals take away market share.
Toyota said its global output tumbled 47.8 percent in April to 308,555 vehicles while Honda Motor Co <7267.T> said its production fell by 52.9 percent.
Nissan Motor Co <7201.T> logged a 22.4 percent decline.
The tsunami and a nuclear power crisis, which triggered power supply disruptions, have halted production of key semiconductors and diodes as well as resins, paint materials and rubber parts.
Automakers are trying to speed up efforts to resume full output, and some key suppliers have said that the recovery in production is moving forward a few weeks faster than planned.
(Reporting by Mayumi Negishi and Taiga Uranaka; Editing by Edwina Gibbs)