Further testing after the detection of a potentially devastating oyster parasite in Foveaux Strait appears to show the outbreak is not widespread.
Bonamia ostreae was found on three wild oysters near Stewart Island during routine testing last month.
Although the parasite isn't a food safety issue, the discovery raised concerns for the Bluff oyster fishery.
Bonamia ostreae was first detected in New Zealand in 2015 in Marlborough, and in 2017 millions of flat oysters had to be destroyed after it was found in Big Glory Bay in Stewart Island.
According to the latest tests by Biosecurity New Zealand, the parasite has not been detected in any of the 322 samples taken from 13 sites in Foveaux Strait.
Dozens of other samples which were taken to test for a different strain of parasite called Bonamia exitiosa are now being retested for Bonamia ostreae.
The results from these tests are expected by late April, Biosecurity New Zealand said.
A rāhui in the area remains in place to protect the Foveaux Strait oyster fishery from potential spread of the parasite.