Poaching at Te Angiangi Marine Reserve appears to be on the increase after two different groups were caught taking sea life during one week in December.
On December 20 two women were apprehended gathering kina at Blackhead Beach inside the south boundary of the reserve.
A week later on December 27 a large group was stopped at Aramoana with 128 kina they had gathered inside the reserve's north boundary.
The sea life was seized and returned to the reserve.
Department of Conservation (DoC) manager Dave Carlton said that in both cases rangers had apprehended the offenders after calls from members of the public.
He said it was concerning that both groups claimed not to know of the reserve, which had been located at the site since 1997.
Both groups had also parked less than 10m from marine reserve signs, and had gathered in full view of large orange triangles.
DoC ranger Rod Hansen said: "In both cases they said they didn't know, but they passed at least six signs on the route to the reserve."
Mr Hansen said there had been 13 major prosecutions for offending against the reserve in late 2013 and early 2014.
Since then, he said the reserve had enjoyed a fairly low level of offending, but this appeared to be on the increase.
In October two men on the reserve were confronted by members of the public, leaving behind a bag of 70 paua, 34 under the legal size limit.
In 2014 a Flaxmere man was fined $850 after attempting to take four kina from the reserve.
Marine reserve offences are strict liability and offenders cannot claim they did not know of the reserve or that they had not seen signage.
People found offending under the Marine Reserves Act can face fines of $10,000, three months in prison and/or forfeiture of property.