A motorist rides across a bridge as Mount Agung volcano erupts near Kubu in Bali.

:: Indonesian authorities on Tuesday extended the closure of the international airport on the resort island of Bali for a second day over fears of a volcanic eruption.

Bali’s Ngurah Rai airport will remain closed until at least Wednesday morning local time.

“The Volcanic Ash Advisory shows that the plane routes have been covered by volcanic ash, this is dangerous for the flights,” Indonesian AirNav official Wisnu Darjono said.

Massive columns of thick grey smoke that have been belching from Mount Agung since last week have now begun shooting more than three kilometres (two miles) into the sky, forcing hundreds of flights to be grounded.

Authorities on Monday warned that the rumbling volcano could erupt at any moment, as they raised alert levels to maximum and accelerated a mass evacuation. The international airport closure left thousands of tourists stranded on the Indonesian holiday island.

Some 40,000 frightened people have fled their homes around the volcano but as many as 100,000 will likely be forced to leave, disaster agency officials have said.

The exclusion zone around Agung, which is 75 kilometres away from the beachside tourist hub of Kuta, has also been widened to 10 kilometres.