NEW YORK (AFP) - Activist physicians on Monday accused the World Health Organisation of downplaying the health impact of nuclear fallout from the Fukushima nuclear disaster.

In a New York symposium marking the two-year anniversary of the Fukushima nuclear plant meltdown in Japan, the physicians took issue with WHO's conclusion in a recent report that it did not expect a significant surge in cancer in Japan or elsewhere due to radiation leaks.

"It's a report that was meant to reassure people who, almost certainly, many will develop leukemia and cancer," said Ms Helen Caldicott, a prominent anti-nuclear activist whose foundation, the Helen Caldicott Foundation, co-sponsored the symposium, along with Physicians for Social Responsibility.

"What is going to happen is there will be a high incidence of cancer and leukemia and genetic disease," due to the leaks, she said.

The WHO report drew criticism from Japanese government officials because it projected an increase in some cancers among those living near the plant.

Japanese officials said the report was based on faulty assumptions and would unnecessarily upset residents.

But Ms Caldicott said the report, released on Feb 28, understated the problem because of key issues it either "ignored" or "glossed over."

For one, she said, WHO did not take actual radioactive emissions into account, relying on estimates.

The UN health body also did not examine the effects on children comprehensively, including what the impact would be of eating radiation-contaminated food over a lifetime.

The agency also did not closely examine the impact on workers at the Fukushima plant or on people from the area who evacuated through the plume of radiation that came from the plant, she said.

"As a physician, I abhor what they've done," Ms Caldicott said.

The two-day conference at the New York Academy of Medicine marked the anniversary of the 9.0-magnitude subsea earthquake and tsunami which rocked Japan on March 11, 2011, leaving nearly 15,881 people dead and 2,668 others still unaccounted for.

The quake and tsunami deeply damaged the cooling systems of the Fukushima nuclear plant, causing partial meltdowns in several units and spilling radioctive particles into the air and sea nearby.

Monday's symposium featured presentations from biologists, epidemiologists and other scientists on the health effects of nuclear accidents.

Ms Caldicott cited one survey done by a Fukushima medical organization that showed 42 per cent of 100,000 children sustained thyroid abnormalities, such as a cyst or a nodule.

The survey showed three children with thyroid cancer and seven additional cases of suspected cancer.

She said data showed that three times as much radioactive xenon, and possibly three times as much cesium, escaped at Fukushima as at Chernobyl, the nuclear plant in the Ukraine that released huge amounts of radioactive particles into the atmosphere after an explosion and fire in 1986.

The WHO report did conclude that the cancer risk was higher for certain groups of local people in Fukushima.

That includes a projected seven percent increase in leukemia among males exposed as infants, over what would have normally been, and a six per cent higher occurrence of breast cancer among women exposed as infants.

The occurrence of thyroid cancer in females over a lifetime could rise by as much as 70 per cent over the normal rate.

But for the general population inside and outside of Japan, the WHO said, "the predicted risks are low and no observable increases in cancer rates above baseline rates are anticipated."

Mr Steven Starr, a programme director at the University of Missouri, presented data from Chernobyl that showed, 14 years later, that 40 per cent of high school graduates suffered chronic blood disorders and malfunctioning thyroids.

Starr predicted similar problems in Fukushima.

Ms Maurice Enis and Ms Jaime Plym, two US Navy quartermasters, told the symposium that they experienced the effects of radiation poisoning after servingon a search and rescue mission near Fukushima after the disaster.

Enis complained of loss of energy, hair loss and the appearance of some lumps on his body.

Ms Plym said her menstrual cycle has been thrown off due to exposure to radioactive materials. They said troops were kept in the dark about the severity of the nuclear incident at Fukushima.

The two have joined a lawsuit with 115 current and former US military personnel against the nuclear plant's owner, Tokyo Electric Power Company, that alleges TEPCO misrepresented the depth of problems at the plant.