The anti-terror raids of October 15 resulted in the seizure of only four weapons and 230 rounds of ammunition that have led to charges.
The early-morning raids involved more than 300 officers.
The police have not said what they seized in the property searches in Auckland, Waikato, the Bay of Plenty, Wellington and Christchurch using warrants alleging crimes under the Terrorism Suppression Act and have declined a request to do so.
But of 16 people charged with firearms offences, items seized on October 15 are the basis of charges against only two - Tame Iti, and a man who has name suppression.
The charges Iti faces include illegal possession on that date of three rifles - a Ruger, a Siga and a Machtech - while the other man is charged in regard to a Ruger rifle and 100 rounds of .22 calibre bullets and 130 rounds of .303 calibre ammunition.
The police said it was inappropriate to comment about matters before the court.
Many of the 16 are charged jointly with up to 12 others and the dates the offences are alleged to have occurred relate to dates of the alleged training camps in the Ureweras.
The earliest charges relate to November 2006.
The Crown predominantly appears to rely on evidence from surveillance of the camps and interception of conversations. While the latter would be admissible for charges under the Terrorism Suppression Act, it is unlikely to be for firearms charges.
Meanwhile, the Solicitor-General says he has no plans to provide a detailed assessment of flaws he identified in the Terrorism Suppression Act, which he said was "almost impossible to apply in a coherent manner".
His criticism prompted the Government to refer the matter to the Law Commission.
An Auckland University specialist in criminal procedure, Associate Professor Scott Optican, said Dr Collins' input would be invaluable to the commission because he had assessed the evidence and the terrorism law.
"How can the Law Commission comment on the sufficiency of a law unless they know exactly what are the problems alleged with it with respect to the facts of this case," said Professor Optican, a former prosecutor.
"I haven't been convinced enough to know whether there really is a problem in the law or [whether] the case just failed for lack of proof.
"You have to make a rational argument as to what is wrong with the law and why you want it to get at behaviour that it doesn't get at. Just to say the law is rubbish isn't enough; you have to be very specific in light of the facts of the case."
A spokeswoman for Dr Collins said he was not doing a report on the matter and had not been asked to.
But it was usual for the commission in the course of reviews of legislation to consult all agencies with an interest in the particular legislation.