The law establishing NIWA gave it the following statutory roles:

• Provide regulation for inland water navigation;
• Ensure development of infrastructural facilities for a national inland waterways connectivity with economic centers using the River Ports and nodal points for inter-nodal exchanges;
• Ensure the development of indigenous technical and managerial skills to meet the challenges of modern inland waterways transportation;There are several other functions and powers of the authority properly enunciated and documented in laws establishing NIWA (NIWA ACT CAP N47 LFN 2004).

Other functions and powers of the Authority:

• undertake capital and maintenance dredging;
• undertake hydrological and hydrographic surveys:
• design ferry routes:
• survey, remove, and receive derelicts, wrecks and other obstructions from in land waterways;
• operate ferry services within the inland waterways system;
• undertake installation and maintenance of lights, buoys and all navigational aids along water channels and banks;
• issue and control licenses for inland navigation, piers, jellies, dockyards;
• examine and survey inland water crafts and shipyard operators;
• grant permit and licenses for sand dredging, pipeline construction, dredging of slots and crossing of waterways by utility lines, water intake, rock blasting and removal;
• grant licenses to private inland waterway operators;
• approve designs and construction of inland river crafts;
• approve and control all (i) jetties, dockyards, piers within the inland waterways;
  (ii) advertising within the right-of-way of the waterways:
• reclaim land within the right-of-way;
• undertake the construction, administration and maintenance of inland river-ports and jetties;
• provide hydraulic structures for river and dams, bed and bank stabilisation, barrages, groynes;
• collect river lolls;
• undertake the production, publication and broadcasting of navigational publi­cations, bulletins and notices, hydrological year hooks, river charts and river maps;
• carry out consultancy and contractual services;
• represent the Government of Nigeria at national and international commissions that deal with navigation and inland water transportation;
• subject to the provisions of the Environmental Impact Assessment Act, carry out environmental impact assessment of navigation and other dredging activi­ties within the inland water and its right-of-ways;
• undertake erection and maintenance of gauges, kilometre boards, horizontal and vertical control marks;
• advise government on all border mailers that relate to the inland waters;
• undertake acquisition, leasing and hiring of properties;
• run cruise boats;
• carry out boat repairs, boat construction and dockyard services; and
• clear water hyacinth and other aquatic weeds.