Evacuees continue to stream into camps as the Agung Volcano Observatory on Tuesday reported an "unprecedented" level of seismic activity and warned of an increased probability of eruption.

Boxes of instant noodles and water were stacked outside Swecapura sports centre in Klungkung, where more than 3800 evacuees sweltered inside the building and surrounding tent city.

Indonesian President, Joko Widodo, was slated to visit the camp on Tuesday afternoon.

Ade Andreawan from the IDEP Foundation, an Indonesian not-for-profit, urged the public to donate food that was healthier than instant noodles, saying eggs, vegetables, tea and coffee would be more useful.

"Who knows if people will be here for a month, two months..." he said.

The foundation was providing activities for children stranded at the centre and teaching them to cover their noses, eyes, mouths and body if the air was thick with volcanic ash in the event of an eruption.

The International Volcanic Health Hazard Network warns freshly fallen volcanic ash particles can have acid coatings which may cause irritation to the lungs and eyes.

Mr Andreawan said Denpasar had run out of the face masks recommended for volcanic ash and the foundation was trying to source more from Jakarta and Surabaya.

Indonesian Disaster Management Agency spokesman Sutopo Purwo Nugroho said masks were available at the agency's posts but had not yet been distributed.

"It's not urgent unless Mount Agung erupts - then the masks will be distributed," he told Fairfax Media. "What we are distributing now is food and daily needs."

Ngurah Rai Airport spokesman Arie Ahsan said if volcanic ash was present the airport would also distribute masks in accordance with health department standards for volcanic ash.

As of Tuesday at noon, 75,673 refugees had fled the mountain according to Bali's disaster management agency.

"When we talked with the evacuees, the main problem they talked about was their cattle," said Nyoman Suardika, a villager from Lebah Besang Kawan.

"They would go home to tend their cattle during the day."

Mr Suardika and several of his friends decided to lend the evacuees' land for their cattle so they did not have to risk their lives returning to the exclusion zone to feed their stock.

It was an example of the Balinese spirit of generosity authorities have praised since the volcano warning was raised to the highest level on Friday night, amid fears an explosion is imminent.

"We now tend to around 70 cows, before it was 90," Mr Suardika said. "Some evacuees maybe ran out of money and had to sell their cows cheap. So I banned speculators from the area."

For the Balinese people, Hindus Mount Agung is the most sacred mountain and the home of Besakih, the holiest temple on the island.

Various theories have been floated for why the volcano's wrath has been provoked, including visitors committing improper acts on the mountain, known as leteh.

But Mount Agung Climbers' coordinator, Mangku Komang Kayun, who lives at the base of the mountain, said it was irresponsible of people to say the mountain would erupt because the gods were angry.

"I want to sue them to shut them up," he said.

"If it's true that the gods are angry because of the sand mines and climbers or villagers acting improperly on Mount Agung, then what about 1963 eruption? There were no climbers, no tourists then, why did it erupt then?"

"If anything, the gods are more merciful, the gods feels for the community now. In 1963, 1100 people died, now we have warnings, to keep away, to stay safe."

Asked why an eruption appeared imminent Mr Mangku Kayun retorted: "It's a volcano!"