KARANGASEM, Indonesia (AFP) -- More than 34,000 people have fled from a rumbling volcano on the resort island of Bali as the magnitude of tremors grows, prompting fears it could erupt for the first time in more than 50 years, an official said Sunday. 

Indonesia's disaster mitigation agency said the number of people fleeing their homes surrounding the volcano had tripled since Friday amid growing alarm that Mount Agung could erupt at any moment.

"The evacuation process is ongoing and we expect the number of evacuees to continue to rise," the agency spokesman Sutopo Purwo Nugroho told AFP. 

The volcano, the highest point in Bali and located about 75 kilometres (50
miles) from the tourist hub of Kuta, has been rumbling since August. 

Officials announced the highest possible alert level on Friday following the increasing volcanic activity, and urged people stay at least nine kilometres away from the crater.

"I am actually very worried to leave, I left my cows and pigs at home because we were ordered to vacate our village immediately," villager Nyoman Asih who fled with her entire family told AFP.

The international airport in Bali's capital, Denpasar, was anticipating the prospect of closure but no flight schedules had been affected as of Sunday. 

The airport has prepared buses and trains to divert passengers to alternative hubs in neighbouring provinces if the mountain erupts. 

Flight disruptions due to drifting ash clouds are not uncommon in Indonesia, which sits on a belt of seismic activity known as the "Ring of Fire".

Last year more than two dozen domestic and international flights to Bali's neighbouring resort island Lombok were cancelled due to a drifting ash cloud from erupting Mount Rinjani.

Bali officials said the island was still generally safe but urged tourists to stay away from tourism spots located within the danger zone.

Pura Besakih temple, one of Bali's most prominent temples which is located just a few kilometres away from the mountain's slopes, has been closed to visitors since Saturday.