An exclusion zone around the volcano has also been increased
Irish citizens in Indonesia are being advised to following the advice and guidance of local authorities, after a volcano there has been put on eruption alert.
The alert level for Mount Agung on the island of Bali has been raised to level 4 following an increase in seismic activity.
An exclusion zone around the volcano has also been increased to 10km.
A volcanic ash cloud has meant that both Bali and Lombok international Airports are temporarily closed.
"Please heed the advice and guidance of local authorities, and maintain contact with your airlines and tour operators before travelling", the Department of Foreign Affairs says.
Gede Suantika, an official at the volcanology and geological disaster mitigation agency, said: "The volcano's alert level has been raised to the highest level. Constant tremors can be felt."
Authorities have told people living nearby the mountain to immediately evacuate.
The airport in Bali's capital, Denpasar, a top holiday destination that attracts millions of tourists every year, has been closed, causing around 2,000 passengers - mostly from Australia - to become stranded.
Plumes of ash and steam as high as 13,000ft (4,000 metres) have been pouring out of Mount Agung since Tuesday.
Mr Suantika said: "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."
Mount Agung is one of more than 120 active volcanoes extending the length of Indonesia that sits on the so-called Pacific Ring of Fire.
It last erupted in 1963, killing about 1,600 people.
Mount Agung rumbled back to life in September and authorities raised the alert to the highest level, forcing 140,000 people to evacuate.
The volcano's activity decreased in late October and many people returned to their home as the alert was lowered to the second-highest level.
But Mount Agung started rumbling again last week.
Irish citizens who need to contact the embassy in Jakarta can call +62 21 280 94300. Outside of office hours: +62 21 280 94300 or the Department of Foreign Affairs and Trade in Dublin at +353 1 408 2000.
Additional reporting: IRN