Customs has fired nine border workers who have not been vaccinated against Covid-19.
Its deputy chief executive for people and capability Jacinda Funnell said the move complies with public health regulations that came into force this month.
"We regret that these individuals have had to leave employment, and understand what a difficult situation this is for them," she said in a statement.
She said the staff were all in fixed-term employment at the maritime border, and other work could not be found for them.
More than 95 percent of frontline Customs staff have received their first dose of the Covid-19 vaccine, and 85 percent have had their second.
Customs is required to comply with the Covid-19 Public Health Response (Vaccinations) Order 2021, which specifies that Customs must not allow an unvaccinated staff member to carry out work in certain places from 1 May 2021.
From yesterday, 1 May all public and private MIQ workers, contractors and visitors had to provide proof of vaccination each time they enter a facility.
Currently workers are considered vaccinated if they have had one dose of the Covid-19 Pfizer vaccine, but all current workers must have had two doses of the vaccine by 5 June 2021.