The New Zealand government on Wednesday launched a controversial voluntary code of conduct to stop acoustic techniques for offshore oil and gas exploration and seabed prospecting disturbing the country\'s unique dolphin and whale populations. Conservation Minister Kate Wilkinson and Energy and Resources Minister Phil Heatley launched the Code of Conduct for Minimizing Acoustic Disturbance to Marine Mammals from Seismic Survey Operations after months of pressure from environmental and political groups at home and abroad to protect the country\'s Maui\' s dolphin, which is believed to have a surviving population of just 55. The code was developed by the Department of Conservation (DOC) and the Petroleum Exploration and Production Association of New Zealand, with input from industry, scientists, government agencies, industry marine mammal observers and environmental interest groups. \"The code represents best practice for the industry to minimize potential risks to New Zealand\'s whales and dolphins,\" Wilkinson said in a statement. \"A number of new measures have been introduced to improve on earlier guidelines, such as increasing marine mammal observer coverage during acoustic work and undertaking marine mammal impact assessments and submitting them to DOC.\" The new code allowed DOC\'s director-general to specify additional mitigation measures if necessary, and required 24-hour passive acoustic monitoring for marine mammals, which provided the ability to estimate the direction and distance of vocalizing whales and dolphins. \"This code provides world-leading standards for minimizing the impact of oil and gas exploration activity on marine mammals,\" Heatley said in the statement. However, the opposition Green Party branded the code \"too weak\" and called for it to be mandatory. \"The Conservation Minister had an opportunity to really protect our marine mammals, but instead has chosen a weak, watered-down voluntary code that puts oil drillers first and endangered marine mammals second,\" said Green Party oceans spokesperson Gareth Hughes. \"The Department of Conservation\'s comparison of marine mammal mitigation measures worldwide shows that all guidelines/ regulations are mandatory except those of New Zealand,\" Hughes said in a statement. International environment campaign group Greenpeace said seismic testing would continue in ecologically sensitive areas regardless of the guidelines. The acoustic noise from seismic testing could injure or kill marine life in close proximity and the sound could be detected up to 3,000 kilometers away, affecting marine migration, feeding, communication and reproduction, said Greenpeace New Zealand political advisor Nathan Argent. \"Greenpeace has deep reservations about the effectiveness of the Code of Conduct as it\'s a voluntary scheme. In other countries such as the UK and Australia, they are mandatory,\" he said in a statement. Despite the known effects of seismic testing on whale, dolphin and fish populations, the code had no provisions to establish liability or to levy fines. \"This code will do nothing to protect our marine life and ocean ecosystems from reckless deep water oil exploration,\" said Argent.