Japan's nuclear crisis is likely to prompt Southeast Asian states to look more carefully at their plans to tap atomic energy for power generation, the head of the regional bloc said Monday.

Association of Southeast Asian Nations (ASEAN) secretary-general Surin Pitsuwan said Japan's struggle to prevent a reactor meltdown at the Fukushima nuclear power plant will have a "psychological" impact on some ASEAN members.

"They will continue to explore, but I think the sense of urgency will certainly be contained a little bit," Surin told reporters on the sidelines of a regional economic conference in Singapore.

"They will look more deeply, they will look more carefully and they will explore other alternative sources."

Surin was speaking as Japan continued efforts to restore power to the Fukushima plant, which suffered heavy damage from the magnitude 9.0 earthquake and tsunami that struck on March 11.

Workers were temporarily evacuated from part of the plant on Monday after a plume of smoke rose from one reactor, operator Tokyo Electric Power Co said.

Japanese Prime Minister Naoto Kan said engineers were making "slow but steady progress" in dealing with the problem as they raced to fix disabled cooling systems and restore power, and fire trucks sprayed water to help cool reactor fuel pools.

Surin said the impact of the crisis would also drive the search for safer alternative energy sources.

"Alternative energy sources will certainly be given more focus, although that will take time," Surin said.

"They will certainly benefit from this new awareness that nuclear power is not an absolute guarantee for safety, and it will certainly lead to more research into the technology of even nuclear power itself just to convince everybody that it is absolutely safe."

Vietnam has already given the green light for the construction of its first nuclear power stations.

Estimated by experts to cost $11-18 billion, the initial plans call for four reactors with a total capacity of 4,000 megawatts to be built, with at least one expected to be operational from 2020.

Malaysia has also laid out plans to build its first nuclear power plant by 2021 and Singapore said atomic power was an option.

Indonesia and Thailand have also considered nuclear power stations but face strong local opposition at proposed reactor sites.

"Vietnam has been considering the Japanese technology, now it will have to need more convincing," Surin said.

"What happened in Japan is certainly something beyond expectations, beyond calculations, beyond the margin of safety that they have already built into the design... What happened could have some impact psychologically."