UN experts endorsed tests designed to show Japanese nuclear plants could withstand a repeat of last year's earthquake and tsunami on Tuesday, with the government keen for public acceptance to restart reactors and avoid a summer power crunch.

The Kashiwazaki-Kariwa Nuclear Power Plant in Kashiwazaki, Niigata, Japan, April 3, 2011. [File photo]

The government still faces a battle to restore public trust in nuclear power, however, after the March 11 disaster wrecked the Fukushima Daiichi plant, triggering a radiation crisis that caused mass evacuations and widespread contamination.

The International Atomic Agency (IAEA) team came to Japan at the government's request to review stress tests conducted by Japan's Nuclear and Industrial Safety Agency (NISA) on halted nuclear reactors to verify their could withstand severe events.

"We concluded that NISA's instructions to power plants and its review process for the comprehensive safety assessments are generally consistent with IAEA safety standards," James Lyons, leader of the 10-member team from the Vienna-based IAEA, said on Tuesday.

"We were very impressed with the way Japan quickly implemented the emergency safety measures after the accident in March. They have also been very active in participating in the international community to determine the steps forward," Lyons told reporters.

He pointed out areas Japan could improve on, such as communicating with local communities about stress tests.

"NISA had done a good job in the transparency of information on their website, but we feel that it is also important for them to hold meetings in the vicinities of nuclear power plants to discuss their findings with the local population," Lyons said.

NISA completed a review of the stress tests, which use computer simulations to evaluate a reactor's resilience, earlier this month and said they showed reactors at Fukui prefecture's Ohi plant, the first to be assessed, were capable of withstanding an impact similar to the 9.0-magnitude earthquake and massive tsunami that wrecked the Fukushima plant.

Some experts have questioned the validity of the stress tests, however, saying the IAEA visit was just for show.

"It is obvious that a visit by an international organization advocating nuclear power is part of a political agenda that is built into a story already finished in advance," University of Tokyo professor Hiromitsu Ino and former nuclear plant design engineer Masashi Goto said in a joint statement last week.

Ino and Goto, who serve on a committee that advises on NISA's review of the stress tests, said the tests were insufficient as they only simulate one natural disaster at a time and do not take into account the possibility of the sort of equipment failure and human error seen at Fukushima.

Others suggested the IAEA's stamp of approval would not be enough to alleviate public concern.