The award was presented to Mr Duff on behalf of the Emperor of Japan by the ambassador of Japan to New Zealand, Hideto Mitamura, at the Japanese embassy in Wellington on Friday.
Mr Duff said the acknowledgement was "pretty humbling".
"It's something that you feel proud of being first of all nominated for it and then being awarded it," he said.
"It's the icing on the cake, a culmination of many years of contact with Japanese people.
"The fact there was a lot of people that have had a lot of association with Japan [at the ceremony] made it all the more special too," he said.
He understood only two or three other New Zealanders had been awarded the decoration.
Mr Duff developed an interest in Japan more than 30 years ago when he hosted Japanese tour groups in Otago. He has since had a strong involvement in promoting Japan as a tourist destination for New Zealanders and has assisted with receiving inbound tour groups from Japan.
That tourism-based contact with the people of Japan was his primary motivation for taking Japanese language lessons.
A founding member of the Dunedin-Otaru Sister City Society, Mr Duff served as its president until 2006.
He and the society have actively supported the teaching of the Japanese language in New Zealand schools, and each year since 1995 they have organised a Japanese language competition for high school pupils.
Mr Duff was also instrumental in organising Japan Week celebrations in Dunedin, which featured city-wide demonstrations of Japanese arts and culture.
