JAKARTA - Flash floods and landslides triggered by monsoon rains in Indonesia's East Java have killed at least 23 people, the state Antara news agency said as mopping up operations got underway.

The disaster is the latest to strike on the island of Java, one of the most densely-populated in the world, where scores of people have been killed this year in rain-related catastrophes.

"Until noon (0500 GMT) we have registered 23 dead victims, with most killed in Bendungan subdistrict," the top government official in Trenggalek district, Soeharto, was quoted as saying Thursday.

In hilly Bendungan, 13 people were killed in a landslide that hit three hamlets there after two days of heavy rain, he said according to the report.

Hermanto, who heads operations at the East Java search and rescue agency, told AFP he did not yet have a toll but had sent a team to Trenggalek.

"We are also readying teams from the surrounding districts to help efforts in Trenggalek," Hermanto said.

Flows of water, mud, rocks and other debris swept through Trenggalek district early Thursday and cut the main road linking it to the nearby town of Ponorogo, district spokesman Joko Setiono said, according to Antara.

Setiono said the floods, which hit six subdistricts as well as the district town of Trenggalek, were subsiding. In some areas, the flood had risen as high as two metres (6.6 feet), he said.

Hundreds of houses along with schools and office buildings were hit by the floods after heavy rain swelled the Ngasinan River, Setiono said.

East Java Governor Imam Utomo and other officials toured the worst hit areas to express sympathy to the victims and see what assistance was needed, an official from the province's administration office said.

She said the governor was disbursing financial aid for the families of the dead as well as cash for local officials to buy aid including food.

Waters had already subsided in Trenggalek town by afternoon and the military as well as local officials and residents were busy cleaning up, another local official, Suwanto, told ElShinta radio.

The town's two-storey hospital was innundated, forcing 50 patients to be moved to the second floor, Suwanto said, adding that water had damaged most of the medical equipment.

Flash floods and landslides in Indonesia are not unusual, although monsoon rains typically hit a peak in January.

In February, at least 19 people were killed in Central Java by floods and landslides.

At least 12 people were killed in similar disasters in January on other islands in the archipelago nation, while more than 150 people were also killed on Java in two separate landslides.

Environmental activists have warned of more frequent disasters in Indonesia unless extensive areas are reforested on Java, which has been largely stripped of its original forests.