Greenpeace is marking the first anniversary of the Fukushima nuclear disaster in Japan with worldwide demonstrations and protests against nuclear power.

Activists in 19 countries have started protests against nuclear power in the run-up to the 11 March anniversary of the Fukushima Daiichi plant disaster.

They have already staged flash mobs, hung banners and protested in public areas to highlight their antipathy to nuclear power.

A huge tsunami ripping into Japan's Pacific coastline on 11 March, 2011 set off a horrific chain reaction of events, culminating in the devastating leak at the Fukushima nuclear power plant. Radiation leaks contaminated land, air and water and forced tens of thousands of workers and residents to flee and many of the affected areas declared off-limits even a year later.

Greenpeace was using the anniversary as a timely warning against countries going for the nuclear option. In Asia alone, Indonesia, Vietnam and Thailand are considering using nuclear reactors.

Greenpeace climate and energy campaigner Francis Dela Cruz said the Association of Southeast Asian Nations (Asean) should be focusing less on nuclear power and more on renewable energy.

"Asean should be heading towards the uptake of renewable energy and the use of more energy-efficiency measures because, one, we do not have the wherewithal to address nuclear risks, and two, it is simply the better way," he said.

"Why expose your communities to nuclear radiation if there's a better way wherein you use energy efficiency and renewable energy?"