Ash blows away from Bali, airport reopens

Bali's airport has reopened to the relief of stranded passengers, but authorities are closely watching the wind conditions that have blown volcanic ash into the busy flight path.

The wind swung to the south on Thursday, pushing volcanic ash from Mt Barujari, a volcano within Lombok's Mt Rinjani, away from Bali.

Denpasar's Ngurah Rai airport was expected to stay closed until Friday but on Thursday afternoon it got the green light to reopen.

Big airlines are losing millions of dollars a day as flights are grounded.

Virgin cancelled all flights scheduled for Friday, Jetstar cancelled Friday morning flights and AirAsia waited for further advice.

Centre for Asia Pacific Aviation (CAPA) chairman Peter Harbison estimated the losses at up to $2 million a day.

Peter Marosszeky, from the University of NSW, said there were hidden costs too.

"When you start talking about the reallocation and rebooking of flights, repositioning of aircraft and hotel accommodation, you quickly creep into millions of dollars," he said.

At Denpasar, drinking beer seemed to be the most popular option for stranded holidaymakers to pass the time.

Brisbane traveller Zac Clancy's Jetstar flight was grounded for two days in a row, so he bought a ticket to fly home via Singapore, only to have that flight cancelled too.

Asked what he would do now, he said: "Play pool and have a few Bintangs."

A man who gave his name as "Silly Billy", from Melbourne, said he was happy to "have a few Bintangs and relax" rather than go back to work.

Airport manager Angkasa Pura Ngurah Rai's general manager Trikora Harjo declared the airport reopened at 1430 local time, and said the situation would be evaluated every two hours.

"We're still preparing, in particular, cleaning the runway of ash," he said.

"The planes are also being cleaned now by the airlines.

"I expect that within two hours, they can fly again."