The Problem Gambling Foundation says poker machine outlets are struggling to keep up with the number of gamblers who want to be excluded from their sites.
Since 2003 it has been law that a so-called self-exclusion must be enforced by the gambling site.
But the foundation's research director, Phil Townshend, says managers of outlets are finding it difficult to do so.
He says the way to make exclusion work would be to have photo IDs going into gambling venues, as happens in most of the world.
Mr Townshend says he helped the very first gambler in New Zealand apply for self-exclusion in 2003 - now there are thousands.
He says a person who breaches a self-exclusion can be fined $500 and the outlet $10,000.