"There is a tradition down there that they go and take these gnomes whenever they go away."
Mr Brew said the trio were embarrassed about the thefts and were now being educated about another custom.
"They probably understand the tradition of the New Zealand Police to actually arrest thieves, a long-standing tradition as well."
It was not uncommon for gnomes and garden ornaments to be reported missing, "and it would be amazing to see how many garden ornaments" ended up in the Dunedin student quarter.
Garden ornaments "were quite sentimental pieces to those who own them", Mr Brew said.
Three gnomes had been reunited with their owners but people still missing a garden gnome were urged to contact Oamaru police.
Two 18-year-old men and a 19-year-old woman were charged with theft and were likely to appear in Oamaru District Court next week, Mr Brew said.