In its 2025 national threat assessment report, the service -- known as the PST -- said Russian intelligence had carried out "dozens" of sabotage actions and disruptive activities using proxy actors since late 2023.
"So far, we have not observed any attempts at such actions in Norway," it said. "However, PST finds it likely that Russian intelligence will try to carry out such actions against targets in Norway in 2025."
It added: "Norwegian-owned energy infrastructure may also be a target for sabotage in the year ahead."
PST director Beate Gangas said these were "troubled times" and that Russia remained the "greatest threat against security in Europe."
"Over the past year, Russia has demonstrated its resolve and ability to carry out sabotage operations on European soil. It is likely that this may also affect Norway," she said.
The PST also said Russian intelligence would continue to map Norway's critical infrastructure and try to identify vulnerabilities.
"This type of information can be exploited for subsequent intelligence, influence operations and sabotage activities," it said.
"Our expectation is that actors involved in Norwegian policy-making will continue to be intelligence targets for Russia.
"This is true in particular for actors involved in Norwegian defense, foreign and security policy, but also in the sectors of justice and emergency preparedness, trade and industry, and energy and environment."
Norway is now the biggest single gas supply source to European markets and has increased its security around gas infrastructure assets since Russia's invasion of Ukraine in February 2022.
Since the invasion, several gas pipelines have been hit by alleged sabotage, notably the Nord Stream and Nord Stream 2 gas links in September 2022 and the Balticconnector in October 2023.
Following the Nord Stream attacks, Europe went into overdrive to up its security measures around gas infrastructure, particularly in countries with North Sea gas assets, including Norway, the Netherlands and the UK.
In the months after the invasion, there were also reports of drone sightings and other activity around onshore gas processing facilities and offshore infrastructure in Norway.
A drone was sighted in October 2022 close to the major Karsto gas processing plant, which followed a hoax bomb threat against the Nyhamna processing facility the same day.
Karsto, Nyhamna and the Kollsnes plant are the three main onshore gas processing facilities in Norway with a combined technical capacity of some 330 million cu m/d.
Norway has also beefed up the military presence at its gas infrastructure, with armed forces present and conducting patrols around installations.
It comes as European gas prices remain high. Platts, part of S&P Global Commodity Insights, assessed the benchmark Dutch TTF month-ahead price on Feb. 4 at Eur51.95/MWh.