Hundreds were crowded at Ngurah Rai International Airport, many dressed in shorts, flip-flops and summer dresses, their expressions dour.

Many sat on the floor, exhausted, and one man repeatedly hit a wall in frustration.

"I just kind of want to see my family.... right now it's a bit stressful," British tourist Adam Woo, transiting through Bali after holidaying on the neighbouring island of Lombok, told AFP.

The 23-year-old student said he saw the missiles start flying on the news "and I was a bit worried about my flight" -- especially after Dubai International Airport was hit in Iran's response to a US-Israeli attack.

"Obviously, everyone around the world at the moment is kind of stuck," said Woo.

"All the travel agencies are swamped with people calling in. So, it's literally impossible to even get on the phone with someone."

He said he was looking for an alternative flight via China.

- Frustration -

Around Woo, many at the airport were lugging around heavy luggage with slumped shoulders, frustration etched on many a face.

Many queued on foot and on chairs outside information centres hoping for news on replacement flights, receiving occasional briefings with little news.

The airport's immigration office said in a statement at least 4,400 people had flights to Doha, Dubai and Abu Dhabi cancelled between Saturday and Monday.

With would-be passengers at risk of overstaying their visas, the Bali immigration office introduced a same-day emergency stay permit free of charge for affected foreigners.

Thirty-five have applied so far, according to immigration head Felucia Sengky Ratna.

Airports company Angkasa Pura said 15 flights from Bali to Doha and Abu Dhabi, and vice versa, have been cancelled between Saturday and Monday.

National carrier Garuda Indonesia has grounded all flights to Doha until further notice.