Phonetic segmentation is the procedure which is used in many applications of speech processing, both as a subpart of automated systems or as the tool for an interactive work. In this paper we are presenting the latest development in our tool of automated phonetic segmentation. The tool is based on HMM forced alignment realized by publicly available HTK toolkit. It is implemented into the environment of Praat application and it can be used with several optional settings. The tool is designed for segmentation of the utterances with known orthographic records while phonetic contents are obtained from the pronunciation lexicon or from orthoepic record generated by rules for new unknown words. Second part of this paper describes small Czech reference database precisely labelled on phonetic level which is supposed to be used for the analysis of the accuracy of automatic phonetic segmentation.