Last month, President Michael D Higgins declined an invitation to the event, saying it was too political.
Sinn Fein says the Government has made the wrong call in its decision to attend a service commemorating the centenary of Northern Ireland.
The Minister for Foreign Affairs and the Government Chief Whip will attend the church service in Armagh.
Britain's Queen Elizabeth's also due to attend the event taking place on the 21st of October.
Last month, President Michael D Higgins declined an invitation to the event, saying it was too political.
However, the Government says its role in this matter is distinct from the Presidents.
Sinn Fein TD Matt Carthy says, President Higgins made the right decision not to attend:
Sinn Fein says the President read the public mood correctly when he decided not to attend a Northern Ireland centenary event.
Michael D Higgins declined an invitation to the church service in Armagh, saying it was too political.
Yesterday government confirmed the Minister for Foreign Affairs and Government Chief Whip will attend the event later this month.
Sinn Fein TD Matt Carthy says they should have followed the President's example
:

Speed Enforcement To Increase In Kildare With 21 New Camera Zones To Be Rolled Out In January
Over 400 Motorists Caught Speeding So Far Today, Including A Driver In Kilcock
Transport Minister In Discussions With Irish Rail About Extending Late-Night Trains Beyond Christmas
Tadhg And Mary Should Be Looking Forward To Christmas, Say Gardai As Fresh Appeal Launched
Bus Shelters Treated As Luxury Rather Than Standard, With 500 Kildare Bus Stops In Need Of Upgrades
Recruitment Announcements Don’t Add Up As Garda Numbers Stagnant In Kildare South, Says Local TD
Court Orders Demolition Of 29 Unauthorised Modular Homes Built By Kildare Developer
Chris Rea, 'Driving Home For Christmas' Singer, Has Died Aged 74