STAVANGER, Norway - Equinor's Arctic Johan Castberg oilfield is expected to reach full production of some 220,000 barrels per day in the first half of 2025, a senior company official said on Tuesday.

The oilfield in the Norwegian part of the Barents Sea is set to start pumping by the end of this year and to produce for around 30 years, serving as a hub to tie in nearby discoveries in the future.

"I guess we will reach the plateau during the first half of next year," Grete Birgitte Haaland, Equinor's head of exploration and production in northern Norway, told Reuters on the sidelines of an energy conference.

Equinor operates the Castberg field and has a 50% stake, while partners Vaar Energi and Petoro have 30% and 20% respectively.

Equinor has postponed an investment decision on another arctic oilfield, Wisting, until 2026 due to rising development costs.

"The main challenge is to have a robust project... we are turning every stone there," Haaland said.

Equinor has been criticised by environmentalists for continuing to develop new fields, especially in the Arctic, in spite of Norway's pledge to reduce greenhouse gas emissions.

Haaland said the company aimed to reduce its emissions to net zero by 2050, and new developments in the Barents Sea were only meant to arrest the natural production decline.

Equinor aims to invest up to $6.7 billion in oil and gas offshore Norway until 2035 to sustain production at around 1.2 million barrel of oil equivalent per day, the company said.

(Reporting by Nerijus Adomaitis, editing by Terje Solsvik and Christina Fincher)