Nearly a million people have been evacuated or told to leave their homes in eastern Japan after freak torrential rain caused flooding and left buildings obliterated, two missing and many more stranded.

Warnings have been issued to more than 5 million people as the populous pacific nation is battered by harsh rainfall. Some areas of Japan's principal island of Honshu have received double their usual September rainfall in 48 hours as tropical storm Etau rages across the Island's central strip.

Japanese local television has broadcast images of perilous rescue attempts by helicopters in Joso in Ibaraki prefecture. One elderly couple was shown clutching their two small pet dogs on their roof as the waters of the Kinugawa river swept past them.

Reuters reported a 63-year-old woman was missing after a landslide struck the building where she lived. Another man, believed to be in his 70s, in Joso 56 km (35 miles) north of Tokyo was trapped in his home as the flood waters swept it away.

Japan floods: Couple and their dogs rescued from rooftop after Joso City submerged under water IBTimes UK

Japanese Prime Minister Shinzo Abe said: "The government will work as one to prioritize the safety of the people and do our best to prevent any further disaster."

Japan has worked to improve its disaster response measures in the wake of the country's 2011 earthquake and tsunaimi which left 20,000 dead. The massive tremors precipitated the Fukushima nuclear disaster, the effects of which continue more than four years later.

Fukushima is one of the areas in Japan which has been hit by the massive rainfall. Weather officials predicted at least 200mm (8 inches) more in parts of eastern Japan as the rain continues over the next 24 hours, after which it is expected to stop. In the worst affected areas rainfall reached 600mm.

Part of a hotel in the town of Nikko had collapsed, Japan's Kyodo news agency has reported, but there were no reports of injuries.