Japan's nuclear watchdog on Wednesday postponed the completion of its review on stress tests on the first pair of dozens of idled reactors, an initial step in rebuilding public trust in atomic energy after the worst nuclear accident in 25 years.

Only three of Japan's 54 reactors are online 11 months after a major earthquake and tsunami crippled the Fukushima Daiichi nuclear power plant. Many have been stopped for regular maintenance, during which utilities are conducting stress tests.