Almost all of the "higher risk" workers have been tested, the Port of Tauranga has confirmed.
A port spokeswoman believed most of the workers in the priority group had been tested by the end of Wednesday, aside from those with different shifts or on leave.
About 320 port workers were tested at the Port of Tauranga's dedicated testing facility on Tuesday, the Bay of Plenty District Health Board confirmed, following about 160 workers between midday and 4pm on Monday.
On Friday, the Ministry of Health ordered up to 6000 Port of Tauranga workers to be tested by midnight on Monday. The public health order was then amended on Monday night - extending the testing deadline to 11.59pm on August 20 and clarifying "high-risk" workers.
The amended order stated only "higher risk" workers needed to be tested - those who had direct contact with ships and crews. It was understood they included shipping agents, pilots and stevedores. Port workers with symptoms were also considered high risk and had to be tested by the deadline.
Other port workers who did not fall into these categories still needed to be tested but it was no longer a requirement by law and the testing deadline did not apply, said the Bay of Plenty DHB.
Bay of Plenty DHB incident controller Karen Smith believed the deadline would be met.
"We are continuing to work with the Port of Tauranga and associated companies to prioritise those workers who need to be tested and are confident that we will meet the deadline."
Testing at the port will be ongoing, the DHB interim chief executive Simon Everitt confirmed at the monthly board meeting on Wednesday.
"What we're doing is getting through the initial surge of tests and then, as with the rest of the border controls we'll then move on to some sort of surveillance regime.
"We're still working through what that might look like but it's likely to be at least two-weekly for those people that are considered a higher risk or having contact with a ship crew."
The Ministry of Health said the order applied to ports where it was a greater risk and affected Tauranga because it was "the busiest port in New Zealand by freight". Testing is also under way at eight other ports across the country.
About 500 people were tested across the DHB region on Tuesday. This figure does not include the 320 port workers tested onsite at the Port of Tauranga.