Sweden's Lundin Energy has sold what it said is the world's first oil cargo certified as carbon neutral at the point of production to Italian refiner Saras, the two companies said on Monday.

Oil companies are increasingly trying to market their products as cleaner in an effort to secure a future for the fossil fuel industry in a world where investors, activists and regulators are demanding action to halt climate change.

While Lundin's crude from the Norwegian Edvard Grieg field was certified as carbon neutral from exploration, development and so-called scope 1 and 2 emissions, the major emissions caused by the oil's final use, or scope 3, are not included.

The North Sea Grieg field causes only 3.8 kilograms of CO2 emissions per barrel of oil equivalent, five times less than the global average, Lundin said.

Residual emissions from producing the 600,000 barrel cargo, amounting to 2,302 tonnes of CO2, will be offset via "nature-based" carbon capture, it added without providing further explanation.

A company representative was not immediately available for additional comment.

Lundin has previously said it would invest $39 million in a project to plant eight million trees in northern Spain and Ghana as part of the company's wider $750 million programme to decarbonise its output.

The company said in January that it expects to achieve carbon neutrality for all its operational CO2 emissions from 2025.

"Selling the 'world's first ever certified carbon neutrally produced oil' is a milestone that few, if any, producers will be able to replicate any time soon," Jefferies analysts said in a note to clients.

The certification of the Lundin cargo was provided by Intertek Group, which tests, inspects and certifies that products meet quality, safety, environmental and other standards for clients including Carrefour, ConocoPhillips and Unilever.

"This sale will carry the Intertek CarbonZero Verified mark and details of this and all traceable certifications are publicly listed for investors, traders, regulators and other stakeholders," Intertek said in a separate statement.

Lundin has told Reuters it was also looking at certifying barrels from Equinor-operated Johan Sverdrup, western Europe's largest oilfield by production, in which it holds a 20% stake.

Texas-based Occidental Petroleum said in January that it had sold the first 100% carbon neutral crude cargo, offsetting emissions by buying carbon credits on the market. However, the transaction itself has not been certified by a third party, unlike Lundin's deal with Saras.