OSLO, Aug 18 (Reuters) - Norwegian oil and gas firms have raised their investment forecasts for 2022 and 2023 as they plan to explore more and develop new projects, a national statistics office (SSB) survey showed on Thursday.

The biggest business sector in Norway now expects to invest 172.8 billion Norwegian crowns ($17.7 billion) in 2022, up from a forecast of 167.2 billion crowns made in May, SSB said.

Next year's investments are seen at 135.3 billion crowns, up from the previous view of 130.6 billion crowns, but the figure is expected to increase as companies plan to approve more projects by the end of this year, it added. ($1 = 9.7468 Norwegian crowns) (Reporting by Nerijus Adomaitis, editing by Terje Solsvik)