Oil Search Ltd., said Exxon was able to raise $1.5 billion to help move the multibillion-dollar project toward completion.
Exxon said last month the project was more than 90 percent finished.
"We are pleased that the supplemental project financing has been completed and all funding is now in place to complete the project on time and within the revised budget," Peter Botten, managing director of Oil Search, Exxon's national partner, said in a statement.
The project will produce as much as 6.9 million tons of LNG at peak capacity once it starts operations next year.
Papua New Guinea has rich deposits of oil and natural gas, with mineral and oil exports accounting for the bulk of the country's gross domestic product. Oil Search said the estimated cost of the project remains unchanged at $19 billion.