Environmental groups are suing Norway for issuing oil exploration licences, despite signing up to the Paris agreement on climate change.
They are challenging 10 licences issued last year to explore the Barents Sea above the Arctic circle.
Greenpeace says global energy companies have already discovered more oil and gas than the world can safely burn.
Norway denies it is breaking a constitutional commitment to safeguard the environment for future generations.
Greenpeace, which is joined by the Nature and Youth group in bringing the case, says the licences – the first to be issued in 20 years – are in violation of the Paris agreement and the Norwegian constitution.
They accuse Norway of violating a section of the country’s constitution, amended in 2014, that guarantees the right to a healthy environment.
Greenpeace’s director in Norway, Truls Gulowsen, told the BBC the world could not safely use all the oil and gas that is already known about, so it was wrong to seek even more.
“Our main logic here is to address the challenge that the world as such has already found more fossil fuels than the world can already burn, in order to combat climate change within two or 1.5 degrees.
“So this is not about Norway’s emissions only. It’s about the imbalance in the world’s carbon budget and the need for fossil-fuel-producing countries to stop looking for more oil when we have already found more than the world can afford that we continue to burn.”
Norway’s attorney general, who is representing the state, will argue that the oil licences awarded to Statoil, Chevron, Lukoil, ConocoPhillips and others have no link to the constitution.
The Paris agreement seeks to limit average global warming caused by greenhouse gases from fossil-fuel burning to under 2C (3.6F) over pre-industrial levels, and to 1.5C if possible.
Norway oil: Environmentalists sue over oil exploration