Several villages have been blanketed by thick clouds of ash as Indonesia’s most volatile volcano on the main island of Java has exploded for a second time in four months.

Mount Merapi erupted in early March, spewing sand and pyroclastic material, sending a massive smoke-and-ash column as high as 6000 metres into the sky, forcing hundreds of villagers to stay several kilometres away.

Indonesia’s Volcanology and Geological Hazard Mitigation Centre advised Mount Merapi erupted again on Sunday, but did not raise the volcano’s alert status, which already was at the third-highest level since it woke last August.

Villagers living on Merapi’s fertile slopes are being advised to stay three kilometres from the crater’s mouth and should be aware of the dangers of lava, the agency said.

The 2968-metre mountain is the most active of 500 Indonesian volcanoes.

Merapi is located on the border between Central Java and the Special Region of Yogyakarta provinces in Indonesia and has been erupting regularly since 1548.

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It has rumbled and generated dark hot clouds since last year.

Its last major eruption in 2010 killed 353 people.

Indonesia, an archipelago of 270 million people, is prone to earthquakes and volcanic activity because it sits along the Pacific “Ring of Fire,” a horseshoe-shaped series of fault lines around the ocean.

-with AAP