China is New Zealand's largest export market and its largest consumer of sheep meat.
China has blocked all New Zealand frozen beef and sheep meat that has arrived there in the past two or three weeks, said Dan Coup, trade and economic manager for the Meat Industry Association of New Zealand.
The meat sitting in freezers at the docks is worth tens of millions of dollars. Because it is frozen, it will last months, Coup said.
Exporters changed the branding on their certificates in March after New Zealand government departments merged. Because the meat is transported in ships, he said, it would have taken several weeks before products with the new branding arrived.
New Zealand Prime Minister John Key said Monday the issue is a technical hiccup that he expects will be resolved this week. He said China continues to have a big appetite for New Zealand meat and he doesn't expect the problem will affect trade long-term.
No other country has halted imports over the matter, New Zealand authorities said.
Other trade between the two countries, including New Zealand's dairy exports, has not been affected.
There are no health or safety concerns and officials are working to resolve the issue, Coup said.
But if the dispute drags on, he said, there's a risk that Chinese buyers will look elsewhere for meat and that exporters will get hit with big storage fees.
New Zealand government figures show meat exports to China increased significantly in the months before the dispute began.
In the first quarter of 2013, New Zealand exported sheep meat worth 204 million New Zealand dollars ($165 million), beef worth NZ$73 million, and edible offal worth NZ$5 million to China. Over the past year, China consumed NZ$600 million of meat. If the pace of the latest quarter continued, the market this year would almost double to NZ$1.1 billion.
"We value our close working relationship with China and remain confident that this issue can be resolved," said Nathan Guy, the Minister for Primary Industries, in a release.