The Waitangi Treaty Grounds have been fenced off for the first time in its history.
The Waitangi National Trust has enclosed the estate with a 930-metre steel fence to make sure that overseas visitors pay for their visit.
Chief executive Greg McManus says the fence will improve security and funnel all visitors through the information centre.
The last two gates were locked on Friday morning, but the trust has listened to the community and provided keys for local people who like to walk the Waitangi coastal track, he said.
For a few dollars, Bay of Islands residents can buy their own numbered key and about a dozen have done so already.
Entry to the Treaty Grounds remains free for New Zealanders, but the trust has lost a lot of revenue over the years from overseas tourists who could walk onto the grounds without paying, Mr McManus said.