The Ormen Lange phase 3 extension is expected to increase gas extraction by up to 40 billion standard cubic metres (bcm), with start-up in 2025, the ministry said.

The field, operated by Shell and located in the Norwegian Sea, will as a result increase gas recovery from 75% to 85%, the ministry said.

"This project helps to maintain the gas supply from Norway to our friends in Europe from the middle of this decade," oil and energy minister Terje Aasland said in a statement.

Seperately, the ministry also approved plans for developing the petroleum discoveries Frosk and Tommeliten A in the North Sea.[L8N2YP2BV]

Tommeliten A, which is partly located on the British side of the North Sea, is operated by ConocoPhillips and co-owned with PGNiG, Totalenergies and Vaar Energi.

Expected recoverable reserves at Tommeliten A are estimated at about 21 million standard cubic metres (mcm) of oil equivalent, of which slightly more than three quarters is gas, the ministry said.

Expected start of production is 2024, it added.

The Frosk discovery, where recoverable reserves are estimated at 1.51 mcm of oil equivalent, most of which is oil, is operated by AkerBP with Vaar Energi as the other stakeholder.

Production is expected to start in 2023.

(Reporting by Victoria Klesty and Nora Buli; editing by David Evans)