More than 130,000 people have fled the region around the Mount Agung volcano on the Indonesian tourist island of Bali, fearing it will soon erupt.

ABC correspondent Adam Harvey reported early on Friday that a column of steam vapour was now visible above the volcano, indicating the mountain is heating up and may erupt at any time.

The ABC reported that the threat of the volcano had left many of the island’s tourist hotspots deserted, with many operators bemoaning the damage to their businesses.

Indonesia’s National Disaster Management Agency spokesman Sutopo Purwo Nugroho said around 135,000 people are now registered with evacuation centres.

They are scattered in more than 500 locations across the island, taking shelter in temporary camps, sports centres and other public buildings.

One of the 500 evacuation centres in Klungkung, Bali. Photo: AAP

The volcano has been at its highest alert level since Friday, sparking the massive exodus of villagers. Thousands of cows are also being evacuated.

An exclusion zone around the mountain extends as far as 12 kilometres from the crater in places but officials say people further from the volcano are leaving too.

Agung, which dominates the landscape in the northeast of the island, last erupted in 1963, killing more than 1100 people and remained active for about a year.

Volcanologists say the recent dramatic escalation in tremors indicates an eruption is more likely than not, but they can’t say with certainty when it will happen.

“I would definitely be following the advice to stay outside the exclusion zone,” said Heather Handley, an assistant earth sciences professor at Sydney’s Macquarie University. The increase in tremors suggests an eruption is “imminent,” she said.

The mountain, about 70 kilometres to the northeast of the tourist hotspot of Kuta, is among more than 120 active volcanoes in Indonesia.

The ABC reported that the town of Amed, about four kilometres outside the Mt Agung exclusion zone and normally bustling with tourists on diving holidays, has emptied.

Cafe owner I Nyoman Kari confirmed to the ABC that the town had emptied of tourists, killing local businesses.

“In Amed, all tourists have gone home because they are afraid of the eruption, two weeks ago, all tourist started to go home,” Nyoman said

“Businesses like the speedboats have been evacuated to a safer place … the speedboats are very expensive, so we wanted to move it away from the ash.”

Disaster Management Agency spokesman Mr Nugroho said many of the people who headed to evacuation centres lived outside the exclusion zone but were uncertain about the safety of their homes.

“The danger line on the map is not clearly visible on the field, hence many people are afraid,” he said.

“Also the number of hoaxes on social media [about an eruption] adds to the level of fear felt by many people including people who live in safe zone.”

– with AAP and ABC