Firefighters search collapsed houses following a landslide in Tanabe, Wakayama prefecture, in western Japan. At least 3,600 people have been stranded by flooded rivers, landslides and collapsed bridges. Kyodo/Reuters

Record rain and mudslides from powerful Typhoon Talas left at least 20 people dead in Japan on Sunday as the storm moved slowly northward past the country's western coast. Another 55 others were missing, local media said.

Evacuation orders and advisories were issued to 460,000 people in western and central Japan. At least 3,600 people were stranded by flooded rivers, landslides and collapsed bridges that were hampering rescue efforts, Kyodo News agency reported.

The typhoon dumped record amounts of rain in some areas, and more was expected. It was the country's worst storm since one in 2004 that left 98 people either dead or missing, the Yomiuri newspaper said.

It turned towns into lakes, washed away cars and triggered mudslides that obliterated houses. People holding umbrellas waded through knee-deep water in city streets and residential areas.

The storm also damaged Nijojo castle in the ancient city of Kyoto, tearing a large piece of plaster from the gate wall. The castle, a popular tourist destination, is designated an important cultural treasure.

Public broadcaster NHK showed a bridge swept away after intense rain caused a river to swell with brown torrents.

Slow storm could trigger more mudslides

The centre of the season's 12th typhoon was moving slowly north across the Sea of Japan off the country's west coast, the Japan Meteorological Agency said. It crossed the southern island of Shikoku and the central part of the main island of Honshu overnight Saturday.

That area is hundreds of kilometres from Japan's tsunami-ravaged northeastern coast.

Because of the storm's slow speed, the agency warned that heavy rains and strong winds were likely to continue and could cause more flooding and landslides. It issued landslide warnings in nearly all of the country's prefectures.

Fears were growing of additional damage from more mudslides because the ground was already soaked.

Three homes were buried in a landslide in Wakayama prefecture. One woman whose identity was still being confirmed died, four remained missing and a 14-year old girl was saved from the debris, police said.

Overall in the hard-hit prefecture, 10 people were dead and 32 people were missing, they said.

Seven people were reported missing in nearby Nara prefecture after their homes were swept down a river, NHK said.

Among the dead was a woman who appeared to be in her 30s whose body was found in a river in Ehime prefecture on Shikoku, police said.

A 73-year-old man in Nara prefecture died after a landslide caused his house to collapse, police said.