The footprints were found in the South Island region of Nelson - the first evidence of the dinosaur's existence in the country.
Geologist Greg Browne of the New Zealand government-owned research organisation, G.N.S. Science, found the footprints while he was investigating rock and sediment formations in Whanganui inlet at Golden Bay, said a press release of Tourism New Zealand here.
The footprints were in six locations spread over an area of about 10km.
Browne said the prints were made by sauropods - large herbivorous dinosaurs with long necks and tails and pillar-like legs.
Palaeontologist Hamish Campbell said the find was 'hugely exciting' and added: 'We will now go and examine rocks of comparable age.'
Browne said the footprints were made in beach sands and were probably quickly covered and preserved by mud from subsequent tides.
'What makes this discovery special is the unique preservation of the footprints in an environment where they could easily have been destroyed by waves, tides, or wind.'
Up to 20 footprints were found at one location and the depressions are roughly circular, with the largest about 60cm in diameter. Most are smaller, typically between 10cm and 20cm in diameter, and were probably formed by dinosaurs between 2m and 6m in length and weighing several tonnes, said Browne.
Dinosaur bones, mostly vertebrae, have been found at three locations - northern Hawkes Bay, Port Waikato, and the Chatham Islands.
Browne said the footprints added a considerable amount of information about how dinosaurs moved, how fast they moved and how big they were.
'This discovery opens the way for further study on a range of dinosaur-related issues in New Zealand.'
Browne's discovery will be published in the December issue of New Zealand Journal of Geology & Geophysics.