MORE than 25,000 people have fled their homes following a series of eruptions and lava flows from a volcano in Indonesia.

Mount Sinabung, on the western island of Sumatra, sent hot rocks and ash up to 5000 metres in the air several times at the weekend.

Mount Sinabung is one of 129 active volcanoes in Indonesia that straddle major tectonic fault lines, known as the Pacific Ring of Fire.

It had been quiet for about 400 years but rumbled back to life in 2010, and again in September 2013.

National Disaster Mitigation Agency emergency response director Tri Budiarto said the situation was extremely dangerous.

"So far, 25,516 people have been evacuated and there is nobody now within a five-kilometre radius of the crater," he said.

"We are urging those living within seven kilometres south-east of the crater to move too."