While 2019 investments are still forecast to hit a four-year high, it is too early to tell whether the industry will see a further increase in 2020, SSB added.

The data is closely watched by Norway's central bank, which has raised interest rates three times in the last year along with a rebound in oil investment from a 2015-2017 slump and a recovery in the price of North Sea crude.

Investments are now seen at 181.7 billion Norwegian crowns ($20.3 billion) in 2019, down from the 183.7 billion crowns predicted in May, according to SSB, which collects the data from oil firms.

In 2020, investments are projected to be 174 billion crowns, higher than the 172.4 billion seen in May, and this number is likely to be raised further in the coming quarters as more project plans are added, SSB said.

"However ... there is still great uncertainty surrounding whether the final investment growth in 2020 will be positive or negative," the agency added.

Norway's crown currency traded around 9.92 against the euro at 0630 GMT, little changed from before the 0600 GMT data release.