Denpasar, Indonesia — Airlines cancelled flights to and from the Indonesian resort island of Bali on Wednesday, leaving travellers stranded after a nearby volcano catapulted an ash tower miles into the sky.

At least 16 international routes were affected after Mount Lewotobi Laki-Laki on Flores island spewed a nine-kilometre (5.6-mile) tower a day earlier, the general manager of Bali's international airport said in a statement.

Flights from Singapore, Hong Kong, Qatar, India, Australia, Malaysia, China's Pudong and South Korea's Incheon were all either delayed or grounded, Ahmad Syaugi Shahab said Wednesday.

Animal clinic worker Samsudin, 52, from Indonesia's main island was transiting in Bali to Malaysia and forced to spend the night at the airport.

"I'm sleeping here rather than going back to Java. It is far," he told AFP.

"I'm waiting here, until tomorrow," he added, saying he bought a new flight after his AirAsia ticket was refunded.

Australia's Jetstar, Qantas and Virgin Australia all grounded flights, while Malaysia Airlines, AirAsia, India's IndiGo and Singapore's Scoot also listed flights as cancelled on Wednesday, an AFP journalist at Bali's airport said.

"Volcanic ash poses a significant threat to safe operations of the aircraft in the vicinity of volcanic clouds," said AirAsia as it announced several cancellations.

Hong Kong's Cathay Pacific also listed its flights as cancelled, rescheduling routes to and from Bali until Thursday.

Multiple eruptions from the 1,703-metre (5,587-foot) twin-peaked volcano in recent weeks have killed nine people, with 31 injured and more than 11,000 evacuated, Indonesia's disaster mitigation agency said Tuesday.

Eruptions can pose serious risks to flights, disgorging fine ash that can damage jet engines and scour a plane's windscreen to the point of invisibility.

The island's tourism head called for calm after the cancellations, saying the island was "very safe" because the volcano is far away.

"Bali's tourism activity is still running normally," Tjok Bagus Pemayun said in a statement Wednesday.

But airlines said the situation was too dangerous to keep their planes in the sky.

Jetstar said all flights to and from Bali would be halted until noon on Thursday as it was "currently not safe to operate flights".

Malaysia Airlines said it had cancelled six flights Wednesday in a statement on its website, while Scoot said it scrapped two flights and rescheduled four more.

The airlines said they would monitor the volcano's status and provide updates.

Singapore Airlines was still listing its flights as running on Wednesday.

'Refunds, rescheduling, re-routing'

Bali airport's Shahab said 26 domestic and 64 international flights had been affected by recent eruptions as of Wednesday afternoon.

"Due to this natural event impacting flight operations, airlines are offering affected passengers the options of refunds, rescheduling, or re-routing," he added in a statement.

But some said they were set to be stranded for days, with little help forthcoming.

"There's nobody helping us, nobody is providing us accommodation or food, we are kind of stranded," said IT consultant Arsh Khurana, 39, from Delhi whose Air India flight was rescheduled to Saturday.

"There is nothing from Air India, there is absolutely no support," he told AFP, adding that he and his wife were set to lose money as the airline's travel insurance did not cover disruptions caused by volcanic eruptions.

Local media reported thousands of passengers were affected but Balinese officials gave no estimate.

Bali's international airport operator PT Angkasa Pura Indonesia said Wednesday it had conducted tests in its airspace and no volcanic ash was detected, saying the airport was "operating as normal".

But the airport in the tourist hotspot of Labuan Bajo on Flores island was shuttered on Wednesday until 8pm local time (1200 GMT) because of the volcanic ash from Lewotobi, according to the airport's Instagram.

Lewotobi erupted again from midnight Wednesday until early morning, and a large ash column could be seen pouring from its crater, an AFP journalist nearby said.

Laki-Laki, which means "man" in Indonesian, is twinned with a calmer volcano named after the Indonesian word for "woman".

The island's economy is heavily reliant on tourism but Indonesia is one of the most disaster-prone nations on Earth, straddling the Pacific Ring of Fire where tectonic plates collide.