The largest piece was a serpentine boulder weighing 185kg.
West Coast Police area prevention manager Paul Watson said a vehicle towing a trailer with the large rock and a number of smaller rocks identified as pounamu was stopped by police in Greymouth in March.
The driver said he got the stone from the Hokitika River.
Inquiries had been ongoing in conjunction with Ngati Waewae.
Chairman Francois Tumahai said they found what was effectively a rock garden containing quantities of serpentine as well as cut and uncut pounamu.
More than 28kg of pounamu with a retail value of about $18,100 was recovered, as well 371kg of serpentine, worth $750.
Mr Watson said they were still in discussion with the runanga - the kaitiaki of pounamu in North Westland - about a course of action, but it could include hefty fines or even prison time.
The penalties on conviction for any pounamu violation would come under the theft and receiving provisions of the Crimes Act 1961, which carried a maximum seven-year prison sentence for stolen property over the value of $1000.
''There may also be reparation ordered for the value of goods stolen if these were not recovered or damaged.''
Mr Tumahai said there was still a large quantity of stone at the property, and it was ''unacceptable practice''.
''Everyone knows who owns the pounamu and at some point in time we've got to put our foot down.''
Constable Shane Allen, of Hokitika, was appointed as the West Coast Police iwi liaison officer seven months ago and has been working closely with iwi to safeguard and protect the resource.
''From our perspective, we've got a good relationship going with local iwi and we want to strengthen that, and we want to show our West Coast community that we are working in strong partnership with local iwi and we will support them in these matters.''
An increase in fossicking was also connected to the drug trade as people tried to fund their habit.
''What we are finding through talking to the legitimate fossickers is that there are just so many footsteps in the sand now ... and they're finding people that are coming from Christchurch and Greymouth who are coming in now just try their luck to make some fast cash.
''There would be a lot that we don't know about that is disappearing off the Coast.''
The recovered stone would not be used.
''Because of what it's been through, it will just go back to the river.''
-By Janna Sherman
-Hokitika Guardian
