Plans would see two 3G artificial pitches developed at Ystrad Mynach for football and rugby with lighting, stands, terracing, car parking and a gym all on the blueprint.
Mr Lewis said, "It's a pleasure for the WRU to be sitting along Caerphilly county council and the FAW. In these changing times we have to be working together.
"The project is an exemplar of how we can work together from elite to grassroots. We totally support and endorse this ambition."