The Reserve Bank of Australia says it expects inflation will start decreasing soon – although not before it's risen first.

In its latest statement on monetary policy, the RBA said inflation will start decreasing early next year, but also warned it will remain higher for longer than previously thought.

"Headline consumer price inflation is expected to peak around 8 per cent at the end of 2022, before starting to decline in early 2023," the statement says.

"This compares with a forecast peak of 7.75 per cent in the August statement.

"The outlook for headline inflation beyond this has also been revised higher, reflecting larger increases in retail prices for electricity and gas in 2023 than previously assumed."

It said there are a number of reasons for the revised forecasts, including flooding in Victoria and NSW driving up food prices.