New Zealand is presently in the early stages of realizing its signficant marine energy resources. The potential is impressively large: this paper addresses likely developments to harness this potential. Openocean wave and tidal current resource have been modelled using hindcast techniques, resulting in an integrated suite of maps at national regional scales. Specific prospective sites have been assessed by the simulation of 3 generic wave and 2 generic tidal current technologies at these sites. 10-year power generation hindcasts enable assessment of the viability of specific sites and the potential timetable and contribution of marine energy deployments to national energy supply.