Four men are facing charges, after an alleged operation where a group of divers overfished paua from remote areas of Wellington, and sold it on the black market.

MPI says the group were diving in isolated areas around Wellington's south coast that were only accessibly with specially equipped 4x4 vehicles.

MPI team manager (fisheries) for the eastern and lower North Island, Mike Green, said the operation came to a head when fishery officers went to an area on the capital's south coast to inspect the activities of two divers.

It was during that inspection that officers discovered the pair had more than 600 paua. That's 30 times the daily limit for two people.

The two vehicles and dive gear used that day were immediately seized.

The seized vehicles. Photo / Supplied

"Following this, four fisheries search warrants were conducted at the addresses of the two divers, as well as another two people identified earlier in our inquiry," Green said.

"As a result, another 4x4 vehicle and more dive gear were seized."

The four men are facing charges under the Fisheries Act, with a maximum penalty of a $250,000 fine or five years in prison.

Their alleged customers could end up in the dock alongside them, as Green said more search warrants were carried out this week at the homes of people believed to have purchased the seafood.

"These people will also likely face serious fisheries charges," Green said.

"Abusing our fisheries and taking in excess of the daily limit for any fish or shellfish is bad enough. This sort of offending has a huge impact on the sustainability of the fishery and creates a localised depletion that impacts everyone.

"Providing and sustaining a black market for those who are taking illegally is equally as bad.

"We will come down hard on everyone involved and we will seize, when applicable, all the gear, equipment, and vehicles used in the commission of an offence."