Toyota says it has resumed production at all of its plants in Japan for the first time since last month's massive earthquake and tsunami.

But the world's No. 1 automaker said the plants would operate at half capacity due to parts shortages.

Toyota spokeswoman Shiori Hashimoto said it remained unclear when Toyota would return to full production in Japan.

The magnitude-9.0 earthquake and ensuing tsunami on March 11 destroyed parts factories in northeastern Japan, causing severe shortages of auto parts.