Eleven people have been killed and thousands forced from their homes this week by flooding on Indonesia's main island of Java, an official said Friday.

Java's longest river burst its banks several days ago after heavy rains and flooded nearly 23,000 houses in Central and East Java provinces, said national disaster agency spokesman Sutopo Purwo Nugroho.

Most of those killed were "swept away by floodwater", he said. Many whose homes were flooded fled to relatives' houses or sheltered in government buildings.

But the flooding had now eased in many areas and people were returning home, he added.

Indonesia is regularly affected by deadly floods and landslides.

Heavy rains caused flooding in the capital Jakarta in January that left 32 people dead and at its peak forced nearly 46,000 to flee their homes.