CPI was up 3.57 per cent from December 2025 and 4.89 per cent from a year earlier.
Prices rose in 10 of the 11 main groups of consumer goods and services, while food and catering services fell 0.03 per cent.
Transport prices posted the largest increase, rising 4.09 per cent month-on-month and contributing 0.41 percentage points to the overall CPI increase.
Diesel prices jumped 22.15 per cent and petrol prices rose 9.53 per cent, reflecting domestic fuel price adjustments in line with global market movements.
Other transport-related costs also increased, with vehicle maintenance services up 0.4 per cent, driving lesson fees 0.37 per cent, car washing and tyre inflation services 0.33 per cent, and spare parts 0.11 per cent.
By contrast, used car prices fell 0.63 per cent, new car prices 0.5 per cent and motorbike prices 0.18 per cent as businesses offered discounts and other incentives.
Passenger rail fares dropped 9.86 per cent, airfares 0.81 per cent and bus fares 0.29 per cent, mainly as travel and tourism demand eased towards the end of the summer peak season.
Elsewhere, kerosene prices rose 4.63 per cent and cooking gas prices 4.19 per cent, pushing housing, utilities, fuel and construction material prices up 0.1 per cent from the previous month.
Average CPI in the first eight months of 2026 rose 4.45 per cent year-on-year, compared with a 3.25 per cent increase in the same period last year.
Food and catering services contributed 1.7 percentage points to the eight-month CPI increase, while housing, utilities, fuel and construction materials added 1.52 percentage points and transport 0.54 percentage points.
Average core inflation rose 4.24 per cent in the first eight months, below the overall CPI increase, as volatile petrol, gas and food prices are excluded from the core inflation measure.
