A preliminary survey found that Afghanistan may have 1.8 billion barrels of oil in the north of the country, an official said.
The survey by Afghan and international geologists found the possible oil field between Balkh and Jawzjan provinces, Mines Ministry spokesman Jawad Omar said.
He said the survey would be reviewed and a statement about the possible field is expected by the end of the year or early in 2011. He gave no further details.
Last June, Afghan officials said US geologists believe the country has nearly one trillion US dollars in mineral resources, although it could take decades and peace with the Taliban and other insurgents before it can be fully exploited.
Oil was first discovered in Afghanistan in 1959 in the country's part of the Amu Darya and Afghan-Tajik basins of the north.
A 2006 report by the US Department of Energy estimated that Afghanistan has about one billion barrels of recoverable oil, although the US Geological Survey the same year put the figure at nearly two billion barrels.