OSLO, June 21 (Xinhua) -- An official report showed Thursday that Norway's production of oil and gas will increase going forward, but new and larger discoveries have to be made in order to maintain the same level after the mid-2020s.

There is a lot of remaining oil and gas on the Norwegian shelf, which still provides significant opportunities in both mature and less explored areas, according to the report published by the Norwegian Petroleum Directorate (NPD).

The estimate for undiscovered resources is 4000 million standard cubic metres of oil equivalents, the NPD said, expecting about two-thirds of them to be located in the Barents Sea while the rest is distributed between the North Sea and Norwegian Sea.

Increased knowledge, more and improved data, new work methods and new technology will create new exploration possibilities and can yield more profitable discoveries, according to the report.

"This report ... shows that after more than 50 years of activity, about 55 percent of anticipated oil and gas resources have yet to be produced. Of these, just under half have not even been discovered," Torgeir Stordal, the NPD's exploration director, was quoted as saying.

"The figures tell us that opportunities on the Norwegian shelf are great and could provide the basis for oil and gas production for decades to come," he said.