The audit took into account a clinic's quality of service and animal care, professional development for staff, facilities, record keeping and medicine management.
A re-audit was done every two years.
Wayne Ricketts, veterinary resource manager for the New Zealand Veterinary Association, said the auditor noted the real commitment to excellence among staff at Tauranga Vets.
"Our auditor was particularly impressed with the enthusiasm and drive to be better that Tauranga Vets demonstrated. They have a modern purpose-built facility and are focused on ensuring procedures and practices meet a benchmarked professional standard."
Dr McDonnell said he expected the accreditation would have a flow-on effect for the business, which employed 22 people across its clinics in Tauranga, Katikati and Te Puna.
Tauranga Vets was a farming-based practice when it was first set up in the early 1940s but today focused on companion, production, equine and lifestyle animals.
"Since the 1980s there has been a change in land use from farming to horticulture, orchards and lifestyle blocks and hobby farms," he said.
Other changes included more alpacas, and fewer deer and dairy farms, though cattle numbers had remained steady.
The changes had created different veterinary needs, he said.
"We've had to move towards a genuine mixed practice."
The broadened focus had motivated the practice to move in 2011 from premises in Devonport Rd to a purpose-built and centrally located clinic in Cameron Rd that was built with Best Practice standards in mind.
The relocation was also the impetus for the company to focus on developing the education and consulting side of the business.
"Being a vet is my passion, but I find myself in charge of a very large business which needs someone 100 per cent dedicated to that as well," said Dr McDonnell.
"There will come a time when we need a practice manager."