Wales International Conference Centre, which will be located on Celtic Manor's resort site, is expected to be completed by the summer of 2018.
It will become the largest facility of its kind in Wales and the south west of England.
The 20,000sqm venue will have an auditorium for 1,300 delegates, which can be divided into smaller rooms.
A 4,000sqm exhibition hall will be able to hold 2,000 delegates, plus an additional 15 meeting rooms and outdoor events space.
The new conference centre will also have a multi-storey car park with 1,500 car parking spaces.
Celtic Manor will be hosting the NATO Summit in September 2014, which Prime Minister David Cameron and President Obama will be attending.
Celtic Manor Resort chairman Sir Terry Matthews said: "We’ve made no secret of our desire to expand our successful business at The Celtic Manor and build on our status as the best conference hotel in the UK.
"It makes me proud to be working with the Welsh Government to deliver the International Convention Centre that Wales so badly needs. It will rival any convention facility in Europe and act as a magnet for major events, bringing huge benefits to the Welsh economy."