After calling for back-up, more officers arrived.
"A fishery officer from MPI was also present and together the officers developed a plan to safely intercept the men after their dive.
"After a six-hour wait, the group emerged from diving not far from where they had parked their vehicles and they were all taken into custody."
Their plunder - 150 paua, 284 kina and five undersized crayfish were seized and returned to the ocean.
A total of $2750 worth of fines was divided among the group and their dive gear and a vehicle was seized.
READ MORE:
• Confessions of a notorious elephant poacher
• Rhino poacher trampled to death by elephant, then eaten by lions in South Africa national park
• Skull of rhino poacher eaten by lions in Kruger National Park found
Sergeant in Charge of Whangamata Will Hamilton said he was "thrilled" with the dedication shown by both police and MPI.
"Many people are not aware that police have powers under the Fisheries Act and can in remote areas, exercise them when MPI officers are not close enough," he said.
"On this occasion, we were lucky to have our MPI colleague and we are grateful for an excellent inter-agency collaboration and result."
Hamilton said the result was down to "both luck and good police and MPI team work."
MPI chief compliance officer fisheries, Jason Howat, said it should serve as a reminder to poachers that they should expect to be stopped and inspected at any time.
"People who continue to abuse our fisheries will be caught and dealt with accordingly," he said.
"We have a lot of coastline to protect and thank police and members of the public that report this sort of activity to us."
Howat said it was another example of local police and fishery officers working together to protect New Zealand's fisheries, which were well supported in the Coromandel.