 Burnet was opposed to the use of nuclear power in Australia owing to the issues of nuclear proliferation. He later retracted his objections to uranium mining in Australia, feeling that nuclear power was necessary while other renewable energy sources were being developed. In the late 1960s and 1970s, he was also vocal in the anti-smoking movement; he was one of the first high-profile figures in Australia to educate the public on the dangers of tobacco, and he appeared in a television advertisement criticising the ethics of tobacco advertising, and broadcasters for displaying such material. He and fellow activists were surprised that the commercial was allowed to run briefly, before being taken off air by the station, which only further generated attention for the anti-smoking campaign. A former smoker, he had rejected the habit in the 1950s after several friends died. Burnet was also a critic of the Vietnam War and called for the creation of an international police force.
