Indonesian and regional authorities heightened flight warnings around Bali's Mount Agung on Sunday as the volcano's eruptions sent a plume of volcanic ash and steam more than 6,000 metres into the skies above the popular holiday island.

Ash covered roads, cars and buildings near the volcano in the northeast of the island, while scores of flights were cancelled and overnight a red glow of what appeared to be magma could be seen in photographs by Antara, the state news agency.

"The activity of Mount Agung has entered the magmatic eruption phase. It is still spewing ash at the moment but we need to monitor and be cautious over the possibility of a strong, explosive eruption," said Gede Suantika, an official at the volcanology and geological disaster mitigation agency.

Bali, famous for its surf and beaches, attracted nearly 5 million visitors last year but business has slumped in areas around the volcano since September when Agung's volcanic tremors began to increase.

Source: Khaleej Times