"As we have seen this year, people everywhere are standing up for their rights and human freedoms."
But all this progress was under threat from economic crisis, rising joblessness and inequality and climate change.
"In these turbulent times, there is only one answer and that is unity of purpose.
"Global problems demand global solutions and that is the very mission of the United Nations."
Although the UN was a victim of its own success, Mr Powles cautioned not to ignore it and push it to one side. One of the principal aims of the UNANZ was to promote understanding and support for the United Nations.
"If it drops too far below the radar, we will see more people and governments ignoring or simply forgetting how valuable the UN is in a changing world," Mr Powles said. "It could then be useless when one day we need it badly."
He was reminded of this point recently when a visiting Australian academic, whose field is in the wider Asia-Pacific region, discussed various proposals that existed for regional security arrangements.
"In the course of the discussion, he remarked that it often puzzled him that so few people accurately identified that the most global security treaty of all time is the UN Charter."
Mr Powles entered the foreign diplomatic service after practising law in Wellington, with "itchy feet from a global upbringing".
He was the ambassador to the UN from 1996-2001, China 1990-93, Indonesia 1982-85 and High Commissioner to Fiji from 1989-1992.