An NSO briefing paper sent to sports groups expressed concern about two key parts of the bill - a move to replace gaming societies with local committees, and the proposal to ensure 80 per cent of grants from gambling proceeds went back into the community where the money was lost.
At present, gaming clubs must give a minimum of 37 per cent of pokie proceeds to the community. Mr Flavell wants to ensure that 80 per cent of this allocation was injected back into the area where the pokie money was collected.
"It is inappropriate ... that money taken out of Kawerau ends up in Balclutha," Mr Flavell said.
The NSO briefing paper said this would severely limit sports organisations' ability to seek funding at a national level.
It concluded that the negative impacts of the bill on sporting groups would be "inversely disproportionate to the good that may be done by the bill to help problem gamblers".
Asked whether the NSO was comfortable with sports being subsidised by pokie proceeds, Ms Castle said: "Gambling is a reality in every society in the world. New Zealand has a fantastic and very unique way of distributing funds to make sure a lot of good comes out of that."
She hoped to gain the support of the NSO's members and take their concerns to the select committee.
Some gaming trusts donated up to 65 per cent of pokie proceeds to the community, much more than the 37 per cent minimum. But most of the large trusts gave around 40 per cent.
Two per cent of pokie proceeds went to a problem gambling levy.
The rest of the proceeds, once 35 per cent was deducted in tax, went to the trusts' administrative costs.