"[We're] not likely to get people coming from the United States because they can see top-quality football at home, [but] it might attract some American football fans from across in Australia.
"The spin-offs tend to be for the accommodation and hospitality sector ... events of this size, if they do get the kinds of numbers they're talking about, it's going to inject many millions of dollars into the Auckland and Wellington economy," Mr Roberts said.
The teams will be made up of professional American football players who are not signed to NFL contracts - meaning any high-profile players who don't make the cut for the American season could be on one of the two teams.
Trials for players are not yet under way, but two high-profile NFL coaches have been confirmed as being in negotiations with Douglas Webber Events.
Herm Edwards and Dick Vermeil both have long histories of coaching in the NFL and the event's managers said they were pleased to have the coaches on board.
The final roster will be announced in September.
Craig Douglas, managing director of Douglas Webber Events, promised New Zealand a world-class event, and said the experience would be "as authentic as possible".
Authenticity meant a blow-out halftime show and Mr Douglas mentioned the possibility of a blimp being flown over the stadiums.
He would not confirm who was booked for the halftime show, but he said "it's big and it's international".
The Dallas Cowboy cheerleaders would be part of the entertainment, he said: the squad was in negotiations with the organisers about performing.
"The likelihood of the girls coming to New Zealand is very high."
Southern Bowl
Auckland, March 5, 2016, Eden Park
Wellington, March 12, Westpac stadium
Tickets are priced from $49 to $129.
