More than 270,000 people have been stranded as volcanic ash from eruptions at Mount Anak Krakatau forced the closure of seven Indonesian airports, including two serving Jakarta.

Ash from Anak Krakatau, which is halfway between Java and Sumatra islands, has blanketed Jakarta and ‌several surrounding areas since it erupted late on Friday, leading to the airport closures.

Indonesia’s transport ministry said on Monday that more than 270,000 people have been affected by the delay, diversion, or cancellation of 2300 flights.

It said Jakarta’s main airport would remain closed until 6pm on Monday (9pm AEST), along ⁠with six other airports. One other airport in South Sumatra has been reopened.

“We ‌cannot ascertain when ​this will end due to the dynamic weather,” Transport Minister Dudy Purwagandhi said on Monday.

Singapore Airlines, Malaysia Airlines, AirAsia and Lion Air Group said they had cancelled flights to and from Jakarta for the rest of Monday.

Flights to and from Bali and other Australian airports have also been disrupted, with travellers urged to contact their airline with queries.

Passengers at Jakarta’s main airport, the Soekarno-Hatta, ​which is located ‌in the city of Tangerang adjacent to Jakarta, were scurrying around, frantically looking for their flight status on the information boards. Some were sleeping on ​benches as they waited for flights to resume.

Carlos Zabala, 24, was travelling to his native Spain after a holiday when he learned his flight was repeatedly delayed. Expressing his frustration, he blamed operators for the lack of clarity.

“All we have to do is wait, and wait, and wait,” he said.

Volcano expert Surono ​told ​Reuters windy and dry conditions were blowing the sulphur and ​silica-laden ash all over the place, and could pose risks to plane ‌engines.

“For Anak Krakatau, the recent eruption was unusual,” he said.

The volcano monitoring agency’s website showed the most recent Anak Krakatau eruption was on Sunday night. It warned on Monday that “the probability of further eruptions in the coming periods remains high”.

At night, the lava from Anak Krakatau lit the sky red as it erupted. Residents were sweeping the dusty floors of their homes and the blackened walls of a nearby mosque.

No casualties were reported and no evacuation order was issued.

The closure of eight airports has affected 170,000 passengers from 1558 cancelled flights. Photo: AAP

The eruptions have brought ash towers as high as 6000 metres on the Java side of the volcano and 15,000 metres on the Sumatra side and in some parts of Banten province in Java, ​meteorological agency BMKG posted on its website.

On Sunday, Indonesia’s disaster agency called for people to wear masks while outdoors to avoid breathing in ​the ash. State news agency Antara reported that schools in Jakarta and Lampung, had gone to remote learning to counter health risks for students.

Anak Krakatau is one of about 130 active volcanoes in Indonesia, which straddles the “Pacific Ring of Fire”, a highly seismically active zone where different plates on the earth’s crust ‌meet to create a ‌large number of ⁠earthquakes and volcanic eruptions.

Anak Krakatau, which means child of Krakatau, began emerging a century ago from the area ​previously occupied by Krakatau, then known as Krakatoa. The older volcano destroyed itself in mass eruptions in 1883, which killed more than 36,000 people after triggering a series of tsunamis.

In 2018, a tsunami after an eruption at Anak Krakatau killed over 400 people.

-with AAP