About 400 junior players turned out in matches during the morning and many stayed on to watch the Citizen Shield match between senior sides Kurow and Valley in the afternoon.
Among those were All Blacks hooker Andrew Hore, who was special guest for the day, handing out presentation packs to teams after the morning matches.
Hore is recovering from injury.
Union chief executive Colin Jackson presented Meridian representative Bob Gray with a montage of photographs of North Otago representative teams to mark its 10-year sponsorship, especially its support of junior rugby.
"Events like this [fun day] and junior rugby would not happen without that support," Mr Jackson said.
Mr Gray described the fun day as "grassroots rugby".
"It's events like this and clubs like Kurow that help our rugby develop," he said.
