Air travel warnings as Bali's Mount Agung erupts

Ash from the eruption covered roads, cars and buildings near the volcano in the north-east of the island

Mount Agung volcano is seen spewing smoke and ash in Bali, Indonesia. Emilio Kuzma-Floyd / via Reuters

Mount Agung volcano erupts as seen from Besakih Temple in Karangasem, Bali, Indonesia. Johannes P. Christo / Reuters

A woman uses an umbrella as she walks through ash from Mount Agung volcano during an eruptiuon in Bebandem Village, Karangasem, Bali, Indonesia on November 26, 2017. Antara Foto / Fikri Yusuf / via Reuters

A farmer ploughs his field as Mount Agung erupts in the background in Culik Village, Karangasem, Bali, Indonesia. Antara Foto / Nyoman Budhiana / via Reuters

Tourists watch the eruption of Mount Agung at a restaurant on Jemeluk Beach, Amed, Karangasem, Bali. Antara Foto / Nyoman Budhiana / via Reuters

Passengers wait for their flight scheduled at Bali's Ngurah Rai International Airport in Bali. Wira Surya / EPA

Balinese Hindus walk after praying as Mount Agung volcano erupts at Besakih Temple in Karangasem, Bali, Indonesia. Johannes P. Christo / Reuters

A motorist rides his motorbike during a shower of ash and rain from Mount Agung volcano during an eruption in Bebandem Village, Karangasem, Bali, Indonesia. Antara Foto / Fikri Yusuf / via Reuters

Villagers carry their belongings during an evacuation following the eruption of Mount Agung, seen in the background, in Karangasem, Indonesia. Firdia Lisnawati / AP Photo

DENPASAR, INDONESIA // A volcano on the Indonesian tourist island of Bali sent plumes of grey smoke and steam thousands of metres into the air on Sunday, triggering flight disruptions and leaving thousands of tourists stranded.

Mount Agung spewed smoke and ash as high as 4,000 metres, causing at least 15 departing or arriving flights to be cancelled on Sunday afternoon, according to a spokesman for Bali's airport.

Indonesia's volcanology centre has put out a red alert warning airlines of a possible eruption, with a likely significant emission of ash into the atmosphere. But Bali's Ngurah Rai airport remained open on Sunday afternoon.

The decision to delay or divert flights was up to individual airlines, airport spokesman Arie Ahsanurrohim said .

"We try to make the airport as comfortable as possible for the passengers affected. So far we have provided special rooms for them to unpack their luggage and video entertainment so they can relax a bit," Mr Ahsanurrohim said.

At least 2,000 passengers are affected by the flight disruption, mostly tourists from Australia.

"I am meant to be at work tomorrow. How am I going to pay my bills?" said Sydney-based tourist Jake Vidler.

On the nearby island of Lombok, also a popular tourist destination east of Bali, the airport was closed on Sunday evening as wind blew ash from Mount Agung in that direction.

"I've received a refund from my airline. Now I'm trying to go to Lombok by boat, hopefully the harbour is open," said Ismono, who like many Indonesians goes by one name.

Mount Agung last erupted in 1963, killing nearly 1,600 people.

It rumbled back to life in September and authorities raised the alert to the highest level, forcing 140,000 people living nearby to evacuate.

The volcano's activity decreased in late October and many people returned to their home as the alert was lowered to the second-highest level.

But Mount Agung rumbled again last Tuesday, forcing at least 25,000 people to seek shelter. Authorities urged people living within 7.5 kilometres of the mountain to evacuate.

The mountain sent smoke up into the air on Saturday for the second time in a week in what volcanologists call a phreatic eruption - one which is caused by the heating and expansion of groundwater.

Officials later on Sunday said the activity could be a magmatic eruption - one which involves the decompression of gas and results in the spewing of ash - and advised people near the mountain to wear masks.

But authorities have decided not to raise the alert back to the highest level just yet.

"This time the tremors and quakes caused by the volcano's activities are significantly less than in September," head of Indonesia's volcanology centre Kasbani, said.

In September hundreds of tremors happened daily near Mount Agung, while during the past few days only a couple of tremors could be felt.

Mount Agung is one of more than 120 active volcanoes extending the length of Indonesia, which straddles the Pacific Ring of Fire.