Footage of flaming lava pouring out of the crater and a tall column of hot cloud rising 1,300 metres into the air was taken by the government-run Merapi Volcano Observatory on Friday night.

The volcano continued to spew hot ash and hot lava was visible on Saturday.

"Residents should anticipate the disruption due to the volcanic ash from Mount Merapi eruption and please be on alert for the danger of volcanic mudflow, especially when it rains around Merapi," the country's volcanology agency said in a statement Saturday.

Merapi also erupted last week, sending volcanic material 9,600 feet (3,000 metres) above the summit.

Volcanic ash rain blanketed at least eight villages near the volcano after last week's eruption.

Volcanologists said last week the volcano is experiencing its most active phase since 2021.

Merapi has been at the second-highest level alert since 2020 following increased volcanic activity and authorities established a restricted zone of seven kilometres from the summit.

The volcano's last major eruption in 2010 killed more than 300 people and forced the evacuation of some 280,000 residents.

It was Merapi's most powerful eruption since 1930 when about 1,300 people were killed. An eruption in 1994 left about 60 people dead.