A census of marine life has found there could be tens of thousands of unidentified marine species in New Zealand's waters.
The census, conducted over a 10-year period, is the largest global research programme to be undertaken on marine biodiversity.
The lead author of the research, Mark Costello, says the National Institute of Water and Atmospheric Research has listed more than 12,000 species.
Dr Costello, an Associate Professor of Marine Ecology at Auckland University, says the census found there are about 4000 un-named species and a further 17,000 still to be discovered.
Scientists expect to eventually name the unknown species using imaging technology previously not available.