Residents and tourists in Bali have been warned they should stay at least 12km from the Mt Agung volcano as the alert level is raised to its highest point.
There has been unprecedented seismic activity around the volcano, a sign an eruption could be imminent.
Indonesia’s National Disaster Management Authority raised alerts for the volcano to level four, the highest point on its scale.
New Zealand's Foreign Minister Gerry Brownlee says Kiwis in and travelling to Bali should register with Safe Travel.
Air New Zealand said it was continuing to monitor the situation and all its Bali services were currently planned to operate as scheduled.
However, passengers should continue checking the airlline's Travel Alert page, as well as the arrivals and departures page for up-to-date information.
Several airlines in Singapore and Australia said they were also preparing for disruptions, but that flights were running normally for now.
Indonesian authorities said flights were diverted to 10 airports including Jakarta, Surabaya, and Lombok on Wednesday. Ferries would also help people leave Bali in case air travel was disrupted.
Bali's Ngurah Rai International Airport is the second-busiest in the country, after Jakarta's main international airport. It was operating normally on Wednesday.
Nearly five million people visited Bali last year, including many from New Zealand, Australia, China and Japan.
Nearly 100,000 residents have so far been evacuated from near the volcano and fears of an imminent eruption have prompted some travelers to rethink holiday plans.
A 4.3 magnitude quake shook the area on Wednesday, indicating that seismic activity remained high, officials said.
"The total number of tremors has decreased, but if we compare the strength (of tremors) it is definitely increasing," said Gede Suantika, an official at national vulcanology agency.
The volcano last erupted in 1963, killing more than 1000 people.
- Reuters and ODT
