The central problems that this paper addresses are (i) the lack of large and rich formalised lexicons for multi-word expressions for use in Natural Language Processing (NLP); (ii) the lack of proper methods and tools to extend the lexicon of an NLP-system for multi-word expressions given a text corpus in a maximally automated manner. The paper describes innovative methods and tools for the automatic identification and lexical representation of multi-word expressions. In addition, it describes a 5.000 entry corpus-based multi-word expression lexical database for Dutch developed using these methods. The database has been externally validated, and its usability has been evaluated in NLP-systems for Dutch. The MWE database developed fills a gap in existing lexical resources for Dutch. The generic methods and tools for MWE identification and lexical representation focus on Dutch, but they are largely language-independent and can also be used for other languages, new domains, and beyond this project. The research results and data described in this paper contribute directly to strengthening the digital infrastructure for Dutch.