Trude Maaseide, a spokeswoman for the prime minister, says Stoltenberg began using his newly purchased iPad while stuck in New York on Thursday, after his return flight was canceled.
Maaseide says the Apple tablet computer was "one of several tools that he used to keep in touch with the office back in Norway, to do his work."
"When we were in the U.S., it was one of several tools that he used to keep in touch with the office back in Norway, to do his work," she told the Associated Press.
She spoke Friday from Basel, Switzerland, where the prime minister was gradually making his way back to Oslo after catching an overnight flight to Madrid.
Volcanic ash sifted down on parts of northern Europe on Friday and thousands of planes stayed on the tarmac to avoid the hazardous cloud. Travel chaos engulfed major European cities and the U.N. warned of possible health risks from falling ash.
Eurocontrol, the European air traffic agency, said the travel disruptions that reverberated throughout the world Thursday were even worse on Friday, with about 11,000 flights expected to operate in Europe instead of the usual 28,000. It said delays will continue well into Saturday as the massive yet invisible ash cloud moves slowly south and east.
"There will be significant disruption of air traffic tomorrow," spokesman Brian Flynn said, adding the agency would hold a meeting Monday of aviation officials from all 40 Eurocontrol countries.