Italian energy giant Eni signed a US$8 billion gas deal with Libya's state-run National Oil Corporation on Saturday as Prime Minister Giorgia Meloni visited Tripoli.

European governments have been scrambling to find alternatives to Russian gas since the war in Ukraine saw deliveries slashed to less than half their previous levels, sending prices soaring to record highs and triggering costly state subsidies to protect consumers.

Eni said it was the first major project in Libya since early 2000 and involved the development of two offshore gas fields.

"The combined gas production from the two structures will start in 2026 and reach a plateau of 750 million of standard gas cubic feet per day," Eni said in a statement.

"Production will be ensured through two main platforms tied in to the existing treatment facilities at the Mellitah Complex," 80 kilometres west of the capital, it added.

"The project also includes the construction of a carbon capture and storage (CCS) facility at Mellitah, allowing a significant reduction of the overall carbon footprint," the company added.

"The overall estimated investment will amount to $8 billion, with significant impact on the industry and the associated supply chain, allowing a significant contribution to the Libyan economy."

Eni has an 80 percent share of Libya's gas production.

The agreement was signed in the presence of Meloni and her host Abdulhamid Dbeibah, who heads the UN-brokered Government of National Unity which is contested by a rival administration in the east.

Her visit is the first by a European leader to war-battered Libya since her predecessor Mario Draghi's visit in April 2021. (AFP)