Thailand's headline inflation rate in August rose slightly from the previous month to a 14-year high, in line with forecast and reinforcing expectations of a further interest rate hike later this month.

The headline consumer price index (CPI) rose 7.86% in August from a year earlier, driven by energy prices and last year's low base, commerce ministry data showed on Monday. That compared with a forecast rise of 7.85% in a Reuters poll.

The pace, the fastest since July 2008, picked up from July's 7.61% rise and was far above the central bank's target range of 1% to 3%. Economists expect a further interest rate hike at the central bank's next meeting on Sept. 28.

The inflation rate, however, may have peaked in August, ministry official Ronnarong Phoolpipat told a news conference.

"Inflation stayed at 7% levels for three months in a row, suggesting it has peaked and will come down if the price situation continues like this," he said.

The ministry sees inflation at around 5% in the fourth quarter and a range of 5.5% to 6.5% in the whole of 2022, he said.

Government support measures, including an energy subsidy, and some price management have helped slow the rise of inflation, he said.

In August, the core CPI index, which strips out energy and fresh food prices, rose 3.15% from a year earlier, lower than a forecast 3.20% rise, but faster than July's 2.99%.

In the January-August period, headline inflation was 6.14% and the core rate was 2.16%.

(Writing by Orathai Sriring; Editing by Martin Petty)