Petronas said it encountered a natural gas layer measuring 958 feet while drilling into its Sintok-1 well off Malaysia and an Indonesian site that tested at 1,656 barrels of oil a day.
The company said the Malaysia discovery is its second of the year at a drilling site off the coast of Sarawak.
The U.S. Energy Information Administration says Malaysia holds the third-largest deposits of natural gas in the region. More than half of its estimated 83 trillion cubic feet of proven natural gas reserves are off Sarawak.
Petronas said in a Friday statement it is trying to determine the overall size of the Indonesian discovery after the initial barrels-per-day test.
Indonesia has struggled to expand oil and natural gas production because of aging infrastructure. The EIA, analytical arm of the U.S. Energy Department, said the country has 3.9 billion barrels of proven oil reserves as of January 2012.