Officials are urgently seeking clarification from Chinese authorities, after exports from two seafood facilities in New Zealand were halted.
It has affected a Sanford facility in Havelock that processes mussels, and a Sealord facility in Nelson that processes finfish and fishmeal.
In late January, both facilities were subject to live video audits by Chinese customs.
The Ministry for Primary Industries said it was advised of the findings and suspensions on Monday evening.
It said the suspensions were due to issues around how Chinese authorities have interpreted the World Health Organization's Covid-19 guidance, and food safety management.
Both premises are complying with New Zealand's Alert level one protocols, it said.
It is seeking urgent clarification.
Seafood company Sealord says it has strict Covid-19 hygiene practices in place and follows China's food safety requirements.
Chief executive Doug Paulin said it had passed all previous Chinese audits and had won an industry award for its Covid safety and hygiene measures.
He said while the suspension was having little material impact, it was important to resolve it.
China has been doing intensive testing of meat and fish at the border despite WHO advice stating the risk of catching Covid-19 from frozen food is low.
About 35 percent of New Zealand's seafood is exported to China - New Zealand's largest market.