The company said it would be ramping up production in coming weeks and LNG cargo deliveries would start soon, in tandem with continued relief efforts.
"One train is currently operating at the LNG plant near Port Moresby. The plant's second train is expected to restart as production is increased over time," Exxon said.
During the shut down, Exxon says it was able to complete unrelated maintenance scheduled for later in the year to allow for more efficient operations in the months ahead.
"Resuming LNG production ahead of our projected eight-week timeframe is a significant achievement for ExxonMobil, our joint-venture partners and our customers," Exxon president Neil Duffin said.
"We will continue to support those communities impacted by the earthquake as we work toward fully restoring our operations. We hope our contributions and assistance will provide comfort to those in need."
In addition to the company's previously announced $1 million contribution for humanitarian relief, ExxonMobil crews have donated and delivered more than 37 tonnes of food, 14 tonnes of drinking water, 600 tarpaulins used as emergency shelters, 1000 solar lights for households, 20 larger solar lighting units for institutions, as well as other essential supplies including water purification tablets, cooking aids and hygiene kits.
The company is also assisting with the restoration of health care facilities and community food gardens, and is providing resources to help the government address the significant task of restoring roads in the Highlands region.
ExxonMobil PNG managing director Andrew Barry said: "While a lot of work remains to be done, we are confident that with the support of all our partners and stakeholders, we can help our friends and neighbours recover from this tragic natural disaster."