Health workers testing for Covid-19 are threatening to walk off the job over pay and conditions, saying mistakes could be made.
Six hundred scientists and technicians at Southern Community Laboratories, which covers Wellington and most of the South Island, are currently in the middle of collective bargaining.
They say they've been working over 12-hour days testing for the virus and staff are being pushed to breaking point.
Senior scientist Rachel Roth is hoping the checks and balances in place for Covid-19 will be enough to prevent failures.
"Given the numbers we're testing at the moment, with staff under stress and working long hours, there is always that possibility," she said.
Southern Community Laboratories is questioning the timing of the strike during a pandemic, saying negotiations have been taking place since June.
It says additional support is being provided.
Partial strike action has been set for next Monday.