But this morning central regional commissioner Terry Buffery said following the return of a negative test result overnight, those staff who were initially sent home as a precaution have been advised they were able to return to work.
The Nikau unit had also been returned to normal.
"It's good news that the test result came back negative and I'm proud of the team at Waikeria who did everything right," said Buffery.
"We know this may have been an unsettling time for the men, and staff will continue to provide them support and answer any questions they may have following the negative test result."
He said management had a duty of care to both staff and prisoners, and the team's quick response to the potential of Covid-19 was a testament to the processes in place from the moment they were notified of any potential exposure to the virus.
Yesterday Buffery said the staffer, who worked in the prison's health centre, was immediately sent home to isolate and get tested after being notified of her close contact status earlier in the day.
Contact tracing identified 52 other staff members as contacts of the original staffer.
In what was described as a "deliberately cautious approach", Buffery said the 52 staff at the facility near Te Awamutu were stood down until the original staffer's test result was returned.
Fortunately, the unit at the centre of the scare was several kilometres away from any other unit. Both the Nikau unit and the health centre had been cleaned.
All staff on site since November 8 had received at least one Covid-19 vaccine dose, thanks to a recent workforce mandate. More than 90 per cent of staff were fully vaccinated.
Eighty-two per cent of prisoners had received their first dose, while 75 per cent had received both.
