The annual inflation rate is now -0.6%, according to latest figures from the Central Statistics Office.
Prices fell 0.8% in January when compared to the previous month, according to to the CSO, with a sharp drop in fuel prices pushing the overall figure lower.
Transport prices were down 3.8% compared to December, according to the CSO, while clothing and footwear prices fell by 10.2%.
The price of alcoholic beverages and tobacco was up 2.3% in the same period, while prices for housing, water, electricity gas and other fuels rose by 2.2%.
On an annual basis, inflation was -0.6% in January – with transport prices falling by 6.6%.
Clothing and footwear prices were down 3.1% annually, while there were also falls in the price of household equipment and food and non-alcoholic beverages during the year.
In the year to January education prices were up 4.9%, while restaurant and hotel prices rose by 1.5%.
The CSO said that its consumer price index must include “goods and services purchased by households for the purposes of consumption” and, as a result, it would now take the newly introduced water charges into account when calculating its figures.