The death toll from landslides and flooding in Indonesia rose to 47 on Monday, an official said, after hundreds of homes were engulfed by surging torrents of mud and rock.

Rescuers used excavators and their bare hands to search through wrecked houses and earth for 15 villagers still missing after days of rain triggered the landslips and flash floods on mountainous Java island at the weekend.

The natural disasters happened across densely populated Central Java province, with fast-moving walls of mud, rock and water engulfing buildings as they raced down hillsides and drivers were swept off roads.

Villagers were trapped on their rooftops and watched helplessly as the rising floodwaters submerged their homes and cars.

PHOTOS: Central Java hit by deadly floods, landslides

Disaster agency spokesman Sutopo Purwo Nugroho said 47 people were confirmed dead and 15 were missing. Hundreds of homes were badly damaged, with some completely flattened.

"People should be prepared as there is still a high potential for flooding and landslides," he warned.

He said that a La Nina weather phenomenon, that typically causes unseasonably heavy rains, could have contributed to the weekend disasters. Java, which should be entering the dry season, has been hit by torrential downpours in recent weeks.

Indonesia and other parts of Asia had been affected by a strong El Nino, which brings drought and sizzling temperatures and is often followed by a La Nina.

He also blamed inadequate preparations, saying that his agency had warned local authorities that heavy rains were coming but it was not clear if they had taken action.

The area worst affected by floods and landslides was Purworejo district, Nugroho said. Deaths were also reported in Banjarnegara and Kebumen districts.

More than 400 rescuers were involved in search efforts. Evacuation centres, equipped with temporary shelters and kitchens, had been set up near the disaster zones.

Landslides and flooding are common in Indonesia, a vast tropical archipelago prone to natural disasters and torrential downpours.