Have your documents notarized by a local notary public
Send the documents to the Legalization Office of the Irish Department of Foreign Affairs
After completing the initial stage of notarisation and legalization, submit the documents to the Chinese embassy or consulate for legalization. Note – This must be done in person or via a service.
See the following link for an overview: http://ie.china-embassy.org/eng/Consular/AuthenticationLegalization/