The public sector is a very big entity and T&C's vary.
When you take up employment will you be part of a superannuation scheme? If so then you can change it to a avc prsa as mentioned by Mula.
If you are not allowed partake in the SA scheme then it might be possible to contiune contributing to your old PRSA. Check with your new employer and whether they allow wage deductions to your provider. (Public Sector organisations not part of the Public Service include such companies as ESB, Bord Gas).
Perhaps you are taking a job in the public service?