Under the current order, employers can be fined up to $15,000 if they employ unvaccinated staff.
Tuesday's protest spokeswoman Louise Burnside, a health professional formerly employed by the Hawke's Bay DHB, said: "Many working nurses received their boosters over six months ago. Further mandates are likely to result in a loss of hundreds more nurses based on what was seen with the last mandated booster.
"Continuing to exclude nurses that refused the vaccine makes no scientific or logical sense. It now seems purely punitive."
In response to the protesters' calls for their jobs to be reinstated, a Hawke's Bay DHB spokeswoman said the DHB was required by law to follow the requirements of the Government's Covid-19 Vaccination Order.
In November, Hawke's Bay District Health Board said 51 staff members, including 17 nurses, had been stood down after refusing the Covid-19 vaccine.
Technical Advisory Services (TAS) - a professional services organisation that provides strategic, advisory and programme management services to DHBs - is collating fresh data on how many health workers were stood down.