Bali governor I Made Mangku Pastika has extended a state of emergency on the island until at least December 10 as it braces for what could be a huge eruption of Mt Agung volcano in the days ahead.
Lombok international airport – on Bali’s neighbouring island – has also been forced to close, according to Indonesia’s ministry of tourism, due to the ash being produced by the mountain.
Lombok is also a major tourist destination in Indonesia.
But weather maps suggest the massive potentially toxic ash cloud is heading its way.
Sutopo Purwo Nugroho, a spokesman for Indonesia’s disaster mitigation agency, posted the weather warning on Twitter with maps showing the predicted journey of the ash.
He said: “Meluruhnya tropical cyclone wind causing Cempaka back to normal to the East-Southeast.
“As a result the Lombok International Airport closed until 30/11/2017 at 24:00.
“Prepare and provide masks.”
In Bali, thousands of locals are being driven to safety as the volcano continues to spew large plumes of white and grey ash.
However hundreds have already fled their homes, with some escaping to Lombok worried about the coming eruption.
Ni Nengah Sari, 38, said: “We will be staying with our family in Mataram as things are becoming worse here.
“Ash from the eruption has blanketed our village.”
Personnel at the Mount Agung evacuee post at Lembar Port confirmed that 16 other evacuees had registered their arrival at the post in Lombok on Wednesday.
The Social Affairs Ministry said it had allocated 500,000 masks, 400,000 of which would be distributed on Bali and the remaining 100,000 were for Lombok.
Margowiyono, the director of social protection at the Social Affairs Ministry, said: “We are distributing the masks among evacuees and citizens who are affected by the eruption.
“The distribution of the masks will be conducted through social affairs agencies.”
Mt Agung continues erupting thick ash up to a height of 1.2 miles (2,000m) and creating a hazardous radius of up to 6.2 miles (10km) from the peak of the crater.
Some airlines have begun cautiously scheduling “recovery” flights from Bali’s Ngurah Rai airport but warn “the situation remains volatile and can change very quickly”.
Experts have also warned Mt Agung volcanic activity could “get much worse”.
From January to September, Bali received 4.5 million foreign tourists, nearly half of the 10.5 million arrivals in Indonesia.
Chinese have overtaken Australians to become the top visitors to Bali, representing around a quarter of arrivals on the island.
Losses in revenue could be more than $650 million since the volcano warning level was first raised in September, Indonesian Tourism Minister Arif Yahya estimated.