A week after huge landslides swamped the Japanese city of Hiroshima, the confirmed death toll from the tragedy hit 70 on Wednesday, with 18 people still missing.

Few hopes remain for those unaccounted for, although the fluctuating number -- which has risen and fallen sometimes independently of the number of dead -- has left confusion as to the disaster's likely final cost in human lives.

More than a month's rain fell in just three hours last Wednesday morning, triggering devastating mudslides on hillside communities in the western city.

Dozens of homes were buried or carried away when tons of earth, rocks and debris smashed into settlements at a reported 40 kilometres (25 miles) per hour.

At its height, the recovery operation involved more than 3,000 police, firefighters and soldiers.

One of their number -- a 53-year-old rescuer -- was swept to his death during the first frantic efforts last week, when a secondary landslide crashed through the area where he was working.

He had a three-year-old boy in his arms at the time. Their lifeless bodies were recovered hours later.

Among those still officially listed as missing was a newly-wed couple who had been expecting their first baby when huge mudslides engulfed their apartment.

They had only moved into their new home a month before the tragedy struck.

Heavy rain has continued on and off since the disaster, hampering search operations amid fears of further landslips as waterlogged hillsides visibly bulged and shifted overhead.