Toxic gases and ash from a still-erupting Japanese volcano have forced rescue workers recovering bodies from the summit to call off their efforts to bring down the remaining victims.

Rescuers were able to airlift eight bodies by a military helicopter before operations were halted at 1:30 pm (04:30 GMT) on Monday, said Naofumi Miyairi, a spokesman for the Nagano prefecture police.

At least 36 people have died. Four victims were flown down on Sunday, and rescuers had returned to the 3,067-metre Mount Ontake on Monday morning to recover the remaining 27.

Five more bodies were found on Monday.

More than 200 soldiers and firefighters, including units with gas-detection equipment, were part of the search mission near the peak, said Katsunori Morimoto, an official in the village of Otaki.

The effort was halted because of an increase in toxic gas and ash as the volcano continued to spew fumes, he said. "It sounds like there is enormous ashfall up there."

The rescuers reported a strong smell of sulphur earlier this morning, Morimoto said.

Scenes broadcast live on Japanese TV station TBS showed soldiers carrying yellow body bags one-by-one to a camouflage military helicopter that had landed in a relatively wide-open area of the now bleak landscape as its rotors were still spinning.

The first bodies were flown to a nearby athletic field, its green grass and surrounding forested hills contrasting with Mount Ontake's ash-gray peak in the background, a reduced plume still emerging from its crater.

There, they were transferred to white police vans, while two dozen officers struggled to hold up long blue tarps under the spinning rotors, blocking the view from the media.

The four brought down on Sunday have been confirmed dead, said Takehiko Furukoshi, a Nagano prefecture crisis-management official.

The 27 others are listed as having heart and lung failure, the customary way for Japanese authorities to describe a body until police doctors can examine it.

Saturday's eruption was the first fatal one in modern times at Mount Ontake, a popular climbing destination on the main Japanese island of Honshu in 210 kilometres west of Tokyo 

Japanese media reported that some of the bodies were found in a lodge near the summit and that others were buried in ash up to 50 centimetres deep.

Police said only two of the four confirmed dead had been identified. Both were men, aged 23 and 45.

Mount Ontake erupted shortly before noon. The blast spewed large white plumes of gas and ash high into the sky, blotted out the midday sun and blanketed the surrounding area in ash.

Hundreds were initially trapped on the slopes, though most made their way down by Saturday night.

Japan's Fire and Disaster Management Agency tallied 40 injured people, three seriously, and said it was trying to update the number still missing.

Source: AP