Dr Dewes gave a seminar on Friday at the University of Otago Centre for Peace and Conflict Studies, on her work over the past five years as an adviser on disarmament issues to the United Nations secretary-general.
She was also involved in other activities at the university last week, including giving a public talk on Thursday with her English-born husband Commander Robert Green, a retired senior officer in the Royal Navy.
Dr Dewes and Commander Green are based at the Disarmament and Security Centre in Christchurch, an organisation which promotes "alternative security".
Dr Dewes said New Zealand had built strong international credibility for its stance against nuclear weapons, with the 25th anniversary of our nuclear-free zone being celebrated this year.
New Zealand was widely respected for its international stance, but the current Government, in its desire to establish closer military links with the United States, was missing some opportunities to take an even more active role to promote nuclear disarmament, she said in an interview.
Because of his strong awareness of the dangers of both conventional and nuclear war on the Korean Peninsula and elsewhere, UN Secretary-general Ban Ki-moon, who is Korean, had "courageously" become the first secretary-general to take the lead by calling for a Nuclear Weapons Convention as part of a five-point proposal aimed at revitalising the disarmament agenda, she said.
The New Zealand public was strongly against nuclear weapons.
Recently, the New Zealand Foreign Affairs and Trade Select Committee had called for the Government to work with "like-minded" governments to begin the process of negotiating a global ban on nuclear weapons.