Exxon’s Rovuma LNG project, jointly operated with Italian firm Eni, will produce, liquefy and sell natural gas from three reservoirs located in the Area 4 block offshore Mozambique’s northern coast.
Exxon estimates the fields, which are due to come on line in 2024, will cost $30 billion to develop.
State television news channel TVM on Sunday said the Ministry of Mineral Resources and Energy would host a signing ceremony with Exxon and other firms in the capital Maputo on Tuesday.
Exxon has said it expects 17,000 tons of liquefied petroleum gas (LPG) per year during the production phase, with the signing of an initial investment decision paving the way for the massive infrastructure project to begin.
The gas fields are located off the coast of the northern Cabo Delgado province, which for the last two years has seen intensifying attacks on surrounding communities and government buildings by an extreme Islamist militant group.
In February Texas-based petroleum firm Anadarko said one worker was killed and several others injured in two related attacks in the Cabo Delgado area where it is building a 17,000-acre liquefaction complex.