DETROIT — Two Japanese automakers are scaling back production at North American plants as they assess their ability to get parts from Japan after that country’s devastating earthquake and tsunami.

Subaru of America said Tuesday it has suspended overtime at its only North American plant in Lafayette, Ind. Toyota Motor Corp. also said it was suspending overtime and Saturday production at its 10 plants in the region.

So far, other Japanese automakers say their North American plants are unaffected.

In Japan, auto companies have shut down production for the rest of the week as they assess damage to plants, ports and roads.

While Japanese automakers with North American plants use locally based suppliers for many of their parts, others still come from Japan.