Norway's combined oil and gas production missed an official forecast by four per cent in September, data from the Norwegian Offshore Directorate (NOD) showed on Tuesday.
Oil production was slightly ahead of projections while natural gas was lagging, the data showed.
Norway is Europe's largest supplier of natural gas and a major producer of oil, but output varies from month to month depending on maintenance needs and other stoppages at its 100 offshore fields.
Overall oil, condensate, natural gas liquids and gas output stood at 0.600 million standard cubic metres per day, equivalent to 3.77 million barrels of oil equivalent, a decrease of 2.3 per cent year-on-year.
Natural gas production in September rose to 298.4 million cubic metres (mcm) per day from 283.9 mcm a year earlier, but lagged a forecast of 319.9 mcm by 6.7 per cent, the regulator said on its website.
Crude oil output fell to 1.73 million barrels per day (bpd) in September from 1.89 million bpd in the same month last year, but came in above a forecast of 1.72 million bpd, NOD's preliminary data showed.
(Reporting by Terje Solsvik, editing by Nora Buli)