Satellite images have detected the volcanic activity on the World Heritage-listed sub-Antarctic island, located 4,100 kilometres southwest of Australia.
Environment Minister Ian Campbell said the volcano had lain dormant for 75,000 years until 1992 when it erupted for the first time.
The last eruption was in 2001, when lava flows doubled the island’s size from 1.13 to 2.45 square kilometres.
McDonald is known for its surrounding treacherous seas which house the Patagonian toothfish, heavily poached by foreign ships.
“The McDonald Island volcano is unusual because unlike most oceanic volcanoes, it sits on a submarine plateau, which means its eruptions are not as wild and fiery as some — instead producing a slow-moving mass of lava that seeps and spreads,” said Senator Campbell.
“Despite the slow-moving nature of the lava, eruptions over the past 13 years have caused startling changes to the island’s geography, obliterating some landmarks and creating new ones,” he said.
He said almost nothing is known of McDonald Island as its uninviting terrain and surrounding hazardous seas make it almost impossible to get ashore, with the last visit made in 2002.
The island is within the Heard Island and McDonald Islands Marine Reserve, one of the world’s biggest at 6,5000 square kilometres.
Heard Island, around 44 kilometres from McDonald Island, also has an active volcano, but it has been quiet for years.
The barren islands, lying in a remote and stormy part of the globe and populated only by large numbers of seal and bird species, were transferred from British administration to Australia in 1947.
Senator Campbell said the 2002 volcano eruption created a pumice beach area, a favoured habitat for king penguin rookeries.
“King penguins, which hadn’t been seen on this island for ever, I think, or a long time, have actually started colonising the island,” he said.