The pay increase is expected to affect tens of thousands of people.
SIPTU members in the public service will receive a pay increase from 1 January as part a Public Service Agreement.
The pay increase will place a particular emphasis on raising the wages of lower paid workers.
From 1 January of next year, public service workers who earn up to €32,000 per year will receive a basic pay increase of 0.5%.
The increase will stand across all departments.
Speaking to JOE, SIPTU Deputy General Secretary, John King said that "tens of thousands" of workers who work in the public sector will be affected by the increase.
He said: "Low paid public service workers who earn up to €32,000 per year will receive a basic pay increase of 0.5% with effect from 1 January 2020.
"This is in addition to the 1.75% paid with effect from 1 September 2019 and will be boosted by a further 2% due on 1 October 2020.
"In addition, the income of public service workers will be further increased on 1 January 2020 with a raising of the threshold on the Additional Superannuation Charge to €34,500 giving an increase of approximately €250 per annum.
"These measures were agreed as part of the provisions of the Public Service Agreement 2018-2020.
"SIPTU remains committed to increasing the standard of living of these workers in any future Public Service Agreements."
