Under current legislation native frogs (Leiopelma) are totally protected species and it is illegal to disturb them, to handle them, to collect them or to specifically look for them without a permit from DOC!
According to the New Zealand Wildlife Act (1953), Section 3 states that “…all wildlife is absolutely protected throughout New Zealand….. except for wildlife specified in the 1st, 2nd, 3rd, 4th and 5th schedules to the Act”. The 5th schedule refers to wildlife that is not protected under the act and states “Amphibians - Green frog (Hyla), Whistling frog (Hyla)” are not protected. So it appears that all species of introduced frogs of the genus Litoria are covered by the 5th schedule and are therefore not protected in New Zealand, however in Section 56(1b) it states that “….no person shall export from New Zealand… any amphibian…” without the necessary permits.
The story becomes a little more complicated when the Conservation Act of 1987 is considered. In this Act, in Section 38(4d), it states that “…it is an offence to possess in any conservation area any animal…”, consequently, introduced frogs do become protected once they occur in a conservation area! Furthermore, in Section 26ZM of the same act, it states that “No person shall transfer live aquatic life or release live aquatic life into any freshwater...” and it defines aquatic life as “…any species of plant or animal life (except birds) that must, at any time of the life history of the species, inhabit freshwater; and includes any part of any such plant or animal…”, so again under this section of the Conservation Act the introduced frogs would enjoy a limited amount of protection.
Strictly speaking it is illegal to release introduced frogs (Litoria) into the wild from a captive situation although this ruling has never been enforced. Bell frog and tree frog tadpoles are commonly sold in pet shops (and on the internet) and are regularly moved between islands. Although this practice is to be strongly discouraged as it may spread frog diseases around the country, most of the knowledge of, and enthusiasm for, amphibians in New Zealand is a direct result of childhood exposure to bell frogs and tree frogs and their tadpoles. Advocacy for indigenous frogs relies heavily on previous exposure to the more charismatic and frequently encountered introduced bell frogs.