Greenpeace, along with environmentalist youth group Natur og Ungdom (Nature and Youth), has sued the Norwegian state over licences it awarded in 2016 for oil prospecting in the Barents Sea.
A third group, called the Grandparents Climate Campaign, has also joined the case against the state.
The plaintiffs accuse Norway of violating the Paris Agreement on climate change and a section of the country's constitution amended in 2014 that guarantees the right to a healthy environment.
A lawyer for the plaintiffs, Cathrine Hambro, asked the court in her opening remarks to determine whether the decision to carry out oil prospecting was "within the existing guidelines for decisions that can have irreversible consequences," news agency NTB reported.
The organisations claim their lawsuit was the first to be filed against a state for violating the agreements signed at the COP21 climate change conference in Paris in December 2015, which came into force in November last year.
"It is clear to us that this new search for oil is in violation of the Paris Agreement and the Norwegian constitution, and we look forward to raising these arguments in court," the head of Greenpeace Norway, Truls Gulowsen, said in a statement on the eve of the first court day.
Norway's oil revenues are dwindling, with crude oil production now half what it was in 2001.
In May 2016, it awarded 10 licences covering a total of 40 blocs to 13 oil companies, including Norway's state-owned mammoth Statoil, US groups Chevron and ConocoPhillips, Germany's DEA, Japan's Idemitsu, Sweden's Lundin, OMV of Austria and Russia's Lukoil.
The NGOs are now calling for the concessions to be cancelled because of the environmental risks.
Norway has insisted it is abiding by the constitution and the "validity of the licences cannot therefore be attacked on this basis," energy ministry spokesman Ole Berthelsen has said.
Three of the most contested licences are located in the immediate vicinity of a maritime border with Russia that has remained unexplored until now, in an area that the two countries long disputed before reaching an agreement in 2010.
One of these zones is the northernmost Norway has ever opened to prospecting, and the NGOs are concerned about its proximity to the ice floes.
"The Norwegian government, like every government, has an obligation to protect people's right to a healthy environment," Ingrid Skjoldvaer, a spokeswoman for Natur og Ungdom, said in a statement.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)