Streams of lava flowed down the sides of Mount Merapi on Tuesday as officials urged people living near the Indonesian volcano to leave the area.

"There's a real sense of imminent doom," Times of London reporter Nick Meo told CBC News in an interview from Yogyakarta Tuesday morning. "Authorities are saying an eruption could happen at any time."

The volcano was spewing rocks and hot ash four kilometres down the mountain's slope, although the clouds of smoke coming from the crater were smaller than they had appeared the day before, Meo said.

"Of course, we don't know whether this means volcanic activity is dying down or whether it's building toward a major eruption."

Scientists believe it's almost inevitable that the volcano's lava dome will collapse, causing a dangerous surge of gas and steam to pour out.

16,000 forced from homes so far

So far, about 16,000 Indonesians have fled the area.

However, efforts to move everyone from the vicinity of the 3,000-metre volcano are being hampered by the presence of an 80-year-old mystic who watches over Merapi.

The man, called Maridjan, makes offerings of rice and fruit to the spirits many Indonesians believe inhabit the sacred volcano.

"He says he's waiting for a vision from them [spirits] to say whether or not the eruption is going to happen," Meo said.

In the absence of such a vision, Maridjan says it's safe to continue living and working near the mountain.

President urges neighbours to flee

That flies in the face of advice from President Susilo Bambang Yudhoyono, who visited the area Monday to urge people to obey the warnings of emergency officials.

"I have learned a lot from past disasters including the [December 2004] tsunami, and from that I can draw that if we conduct very good preparations ... there will be a lot that we can save," Yudhoyono said, according to the Associated Press.

Seventy people died in Merapi's last eruption, in 1994. A much more deadly blast in 1930 claimed 1,300 lives.

The volcano is located about 450 kilometres east of Jakarta on the Indonesian island of Java.