Authorities raised the alert status for Mount Ibu, located on remote Halmahera island, to the highest level of a four-tiered system on Thursday after recording two huge eruptions for the second day in a row.

Residents in seven villages near Ibu -- which spewed ash and smoke 5,000 metres (16,400 feet) into the sky -- began evacuating to several shelters late Thursday after authorities raised the alert status, local disaster mitigation agency official Muhammad Ade Fabanyo told AFP.

"Until today, the evacuees continue to arrive and as of this morning, the preliminary data that we have is around 400 people (evacuated)," Ade said Friday.

He said the evacuation was a "preventive" measure taken by authorities since the residents were living around seven kilometres (4.3 miles) from the volcano -- within the exclusion zone set by officials.

Ibu erupted again on Friday morning, spewing a tower of volcanic ash 4,000 metres above its peak, the country's geology agency head Muhammad Wafid said in a statement.

Authorities advised residents and tourists to stay out of the four-to-seven-kilometre exclusion zone and to wear a face mask in case of falling ash.

Ibu is one of Indonesia's most active volcanos, erupting more than 21,000 times last year.

More than 700,000 people lived on Halmahera island as of 2022, according to official figures.

Indonesia, a vast archipelago nation, experiences frequent seismic and volcanic activity due to its position on the Pacific "Ring of Fire".

Last month, Mount Ruang in North Sulawesi province erupted more than half a dozen times, forcing thousands of residents of nearby islands to evacuate.

Its status has since been lowered to the second-highest alert level.