Nearly 10,000 volunteers work for St John in positions ranging from voluntary ambulance officers to governance roles.
"We could not deliver our emergency services or community health programmes without them", said chief executive Peter Bradley.
Surf Life Saving New Zealand also recognised the work of its volunteers over the busy summer season which saw rescues up 14 per cent on the previous year.
Lifeguards rescued 1513 people over the season, up from 1328 in 2014/15, chief executive Paul Dalton said.
The country's 4513 lifeguards spent 220,000 hours on patrol, 141,690 of which were on a voluntary basis.
He acknowledged the time unpaid workers gave to surf lifesaving.
"Volunteering is a huge commitment, and for many of our members, it's a lifetime commitment."
The Returned Services Association (RSA) said its support network relies on volunteers and "would not exist" without them.
The volunteers' services include collecting on Poppy Day, visiting returned servicemen in hospital and weeding local war memorials.
There are an estimated 1.2 million people volunteering their time in New Zealand, according to Volunteering New Zealand.
National Volunteer Week runs from 19-25 June 2016.