A volcano in western Indonesia erupted Tuesday for the second time this week, hurling a three-kilometre column of red-hot smoke and ash into the sky and forcing thousands more people to flee their homes.

A vast, black cloud hung over Mount Sinabung, on Sumatra island, after it erupted at around midday with a sound like thunder that could be heard for miles around, an AFP reporter at the scene said.

White volcanic ash rained down on surrounding villages, blanketing streets, houses and trees, and prompting people to don masks and put up umbrellas to protect themselves, the reporter said.

Around 3,000 more people fled their homes after the new eruption in the Karo district of North Sumatra province, Robert Peranginangin, local government spokesman, told AFP.

The total number of those who have fled since the volcano first erupted on Sunday was now at 9,420, he added.

He said that those displaced were not only from a three-kilometre (1.9-mile) "danger" zone that authorities had implemented following the weekend eruption.

"They are also people living outside the area as they panicked and decided to move to shelters," he said, adding that 14 evacuation shelters had now been set up nearby.

Hendra Gunawan, a volcanologist at a local monitoring post, told AFP that the volcano hurled ashed three kilometres into the air.

Transport ministry spokesman Bambang Ervan said authorities had warned airlines to take care when flying in the area.

The 2,400-metre high volcano was dormant for nearly 100 years before erupting in August and September 2010, forcing about 12,000 people to flee.

Indonesia has dozens of active volcanoes and straddles major tectonic fault lines known as the "Ring of Fire" between the Pacific and Indian oceans.

Last month five people were killed and hundreds evacuated when a volcano on a tiny island in East Nusa Tenggara province erupted.

The country's most active volcano, Mount Merapi in central Java, killed more than 350 people in a series of violent eruptions in 2010.