The vessel was dispatched on Saturday to help assist people from the northern island of Ambae as Monaro Voui threatens to shower down burning ash and acid rain.
Vanuatu ordered the full evacuation of the island after the nation's largest volcano began emitting volcanic gas last weekend.
Boats will spend the next week ferrying residents off Ambae where the Monaro volcano spewed lava, smoke, and ash since Sunday.
Vanuatu has maintained its danger rating at a threat level four, the second highest, as an onslaught of ships including ferries and commercial vessels begin moving the population to nearby islands of Maewo, Pentecost and Santo.
More than 6,000 people have already been sent to emergency shelters on the South Pacific Island.
HMAS Choules left for Vanuatu on Saturday morning with specialists and supplies, the Australian government have said in a statement.
Vanuatu called for international help through the FRANZ partnership, which groups France, Australia and New Zealand, and aims to evacuate the island by October 6.
The volcano is surrounded by crater lakes which make it far more dangerous, said Macquarie University vulcanologist Christopher Firth.
The sudden activity of the Monaro volcano in Vanuatu shocked residents despite it being active since 2005.
One of the lakes is directly above the eruption increasing its explosive potential and threatening a deadly lahar: a boiling mud flow down the side of the mountain, Firth said.
Australia has committed $250,000(US$195,000) to Vanuatu for supplies including food, water, shelter and hygiene kits, and will assist in aerial surveillance, the statement also said.
New Zealand has also given aid including water, sanitation and hygiene kits and has made $100,000(US$72,000) available for the response, Foreign Affairs Minister Gerry Brownlee said on Saturday.
Vanuatu's National Disaster Management Office said an emergency would be declared for the small island with the activity measure being raised to level four
Vanuatu, a sprawling cluster of more than 80 islands and 260,000 people, is on the geologically active Pacific Ring of Fire and its Tana island active volcano is a major tourist attraction.
Ambrym Island which is in the centre of the Vanuatu archipelago is also erupting from two active cones and is rated at a threat level three. At this stage it is still considered a minor eruption.