Thousands of travellers were stranded at Tokyo's Narita airport on Friday as record rainfall pummelled eastern Japan, bringing floods that disrupted transport, knocked out power to 20,000 homes and killed at least eight people.

Record-breaking heavy rain has pounded eastern Japan, flooding roads and homes, paralyzing traffic, and causing power outages near Tokyo.

Areas around Tokyo have recorded 360mm of rainfall in the 24 hours to Friday, causing widespread chaos and damage, while Hawaii prepares for Tropical Storm Lala.