The clinic - which started yesterday - is being run in collaboration with South Seas Healthcare and union E tu.
It's open from 8am until 5pm for staff, contractors, whanau and members of the public.
NZ Post chief people officer Monica Ayers says the health and safety of the company's frontline workers, its customers and the public is its number one priority.
E tu is hoping other large employers who employer essential workers will follow suit.
