U.S.A. based Apache Corporation said an exploration well off Western Australia's coast had found as much as 300 million barrels of crude.
The finding is being celebrated by some as potentially Australia's largest oil discovery in the last 30 years.
"The oil and reservoir quality we have seen point to a commercial discovery," said Thomas E. Voytovich, a senior executive at Apache's international arm.
"If these results are borne out by further appraisal drilling, Phoenix South may represent a new oil province for Australia."
"It will take two to three months to work out the actual recoverable volumes from the discovery," said Simon Andrew, an energy analyst at Perth-based broker Hartleys.
However, the discovery is not feted in all comments.
"It looks a bit punchy based on the facts we've got today," one analyst said. "There are still a lot of unanswered questions here."
Source: ANA-MPA / The Wall Street Journal / The Sydney Morning Herald