An adjustment to Russia's budget rule next year will make an extra 1.7 trillion roubles ($17.72 billion) available in spending from oil and gas revenues, according to draft outlines for Russia's budget over the next three-year period.

After invading Ukraine in February 2022, Russia suspended its budget rule and introduced a version in 2023 allowing it to spend more and save less in its National Wealth Fund (NWF).

At a government meeting on Friday, Finance Minister Anton Siluanov said Russia would return to following its budget rule in 2024, envisaging an oil price of $60 per barrel, rather than a fixed amount of oil and gas revenues, set at 8 trillion roubles in 2023.

Under its budget rule, Russia sells foreign currency from the wealth fund to make up for any shortfall in revenue from oil and gas exports, or makes purchases in the event of a surplus.

The return to the old formula for calculating the budget rule would give Russia's budget 9.7 trillion roubles next year from surplus energy revenues, the draft budget materials showed.

"If more spending is needed, then some deviations from the budget rule without risks to macroeconomic stability are, in my view, necessary," said Siluanov in June, hinting at a possible tweak.

Russia's finance ministry forecasts total oil and gas revenues in 2024 of 11.5 trillion roubles. Additional oil and gas revenues next year are estimated at 1.8 trillion roubles, which will be credited to the NWF in 2025.

Russia plans to increase budget spending by 25.8% to 36.6 trillion roubles in 2024, Prime Minister Mikhail Mishustin said on Friday, with hefty increases in military and social spending expected ahead of a March presidential election.

Moscow has heavily diverted funds towards the war in Ukraine, which it calls a "special military operation", and social spending will rise around the election in which President Vladimir Putin is expected to seek another six-year term.

The assets in the NWF, Russia's rainy day fund, stood at the equivalent of $142.9 billion as of Sept. 1, or 9.1% of projected 2023 gross domestic product, down from $146.3 billion on Aug. 1. ($1 = 95.9300 roubles) (Reporting by Darya Korsunskaya; Writing by Alexander Marrow; Editing by Philippa Fletcher)