The project involves redeveloping existing resources, and creating over 45ha of new space by reclaiming land at the end of Belfast Lough.
The space will be used for a mixture of port facilities including some container yards.
Another 6km of new quayside will also be created, It will accommodate warehousing and new wharf space.
Port expansion is critical to the future of Northern Ireland said Port of Belfast.
A recent study carried out for the port by London consultancy CEBR, says that it handles 60% share of imports and exports for the region and accounts for 31% of the £19.5bn regional economy. Tax contribution is £3.3bn.
The port also sustains 187,000 jobs either within the port or in support services.
The port will need to increase capacity by 109% to cope with increased demand, says the CEBR report.
Money for the investment is to come from the Port of Belfast revenues including port charges,
property management and rents.
Economic momentum has been picking up for some time as the political peace process has progressed.