Mr Donnelly said event staff would be able to manage alcohol consumption in the ground, but there was nothing stopping punters pre-loading at liquor stores and bars.
``Obviously it's in the middle of a residential area and there's a lot of side streets and places where people aren't visible to police or security,'' he said.
"For eight hours solid, residents are going to be trying to get on with their days - taking kids to and from sport and things - and if it's a crowd that might be aggressive they're not going to want to drive past.''
NRL Nines promotor Dean Lonergan previously told the Herald locals had nothing to fear.
"We are very mindful of the Eden Park ratepayers and very mindful of the surrounding areas,'' Mr Lonergan said.
''... We will do what is appropriate to make sure that everyone who comes in here has a really good time and doesn't have to put up with drunk people.
"It is not in anyone's interest to have drunk people floating around and we'll be doing our utmost to make sure that doesn't happen.''