It takes at least 1 month to get a new passport because the consular office will check your information at the original issuing authorities in China, if you hold the copy of your lost passport, then it will take shorter time. You should report the loss to the local police station, and make a declaration of the expiration of the lost passport at the local newspaper, when you apply for a new passport, you should take the certificate of your China nationality, valid Irish visa or residence permit, the lost report from the local police station, 3 passport photos, one filled passport application form, if you leally live in Ireland for a long time, you will get a Chinese passport, if you just a tourist in Ireland, you will get a Travel Document of PRC.

for more information, please refer to http://ie.chineseembassy.org/chn/lsjqz/zgfzlxz/t108928.htm (in Chinese version)