Consumer prices fell 0.2 percent on the month in September after also dropping 0.2 percent decrease in August, the office said.
Under the EU-harmonised index, where non-food items have more weight, consumer prices fell 1.4 percent on the month and registered a drop of 1.9 percent on the year.
The government sees consumer prices decreasing 1.1 percent on the average this year, while the International Monetary Fund forecasts a drop of 1.2 percent.