The police officer in charge of the case, Sergeant Garth Mackay, agreed.
"I think the person/s responsible have stooped to the lowest of the low - they're amongst collection box thieves."
RSA national president BJ Clark described the incident as "sacrilege to the highest degree".
"For people to remove plaques for the value of the metal, it really does show a complete lack of respect."
RSA funeral officer Gary Murdoch discovered the plaques were missing while doing work in the cemetery at about 9am yesterday and reported it to police.
Mr Murdoch is assessing records to determine who the graves belonged to and said the thefts were likely to be very upsetting to the families.
"They are very, very important to the families."
There are about 300 people buried in the cemetery, over 100 of which Mr Murdoch has buried over the past 15 years. He did not believe the plaques - which are approximately 300mm x 500mm in size - would be onsold for more than a nominal amount.
Sergeant Mackay said the theft of the brass plaques would solely be to generate money from onsale at a scrapmetal dealers.
As for how low you can go, Ed from the Metalman in Whangarei said the public would be surprised at some of the things people try to flog off to scrap dealers.
However, a code of honour as well as laws covering the purchase of scrap metal would make dealers wary of buying items like memorial plaques, he said.
"Most people would come in with some sad story and they're sometimes genuine. Others, well, you'd be surprised."
Paperwork, proof of identification and CCTV on premises mean sellers can be traced fairly easily if the police follow up cases, he said. In the end, the risk is on the dealers if they buying anything shonky, he said.
Doris Boyd from Dargaville-based Little River scrap dealers said she would be looking sideways at anyone bringing in brass grave plaques, but doubted if the ones stolen locally would be offered to a local dealer.
Ms Boyd said the police had been in to speak with her about the theft.
"I would be questioning anyone who brought something like that in here anyway, especially if the name on the plaque isn't the same as one on the plaque."
Both scrap dealers spoken to by the Advocate said the plaques would be worth very little.
Police are appealing for information about the thefts or current location of the plaques. Please call Dargaville Police on 09 439 3400 or Crimestoppers on 0800 555 111 to remain anonymous.