Central Otago police are reminding gold mining companies to be vigilant about the risks of staff stealing alluvial gold.
The call for awareness comes after an Alexandra couple were sentenced in the Dunedin District Court for stealing $24,000 worth of gold.
Detective Alan Lee said while the theft was one of two over the past year and-a-half, it was an unusual occurrence.
''I have been here for five years and I have only been involved in two cases [relating to gold theft] in that time.''
However, gold mining companies should ''keep on their toes''.
Most had good procedures in place to reduce the possibility of offending, he said.
L&M Group chief financial officer Shirley Herridge said the group, which operates New Zealand's largest alluvial gold mine near Alexandra, had ''rigorous and stringent'' procedures in place to prevent gold theft at the mine.
''It's not a big industry and we choose our staff very carefully, to minimise the likelihood of that happening, but nothing is foolproof.''
She could not speak for other companies regarding theft prevention, but thought they would have similar procedures in place.
Details of procedures could not be revealed, as it would compromise the company's ability to minimise theft.
Police said several gold experts and the Central Otago gold mining industry and community assisted in bringing the recent case to court.
Det Lee said experts could identify gold by physical characteristics including colour, shape and texture.
Miss Herridge said the method of identification was called fingerprinting and determined the characteristics of gold from a certain area.
If gold had been fingerprinted it was easy to identify.
A gold industry employee, who did not want to be named, said it was obvious when people were attempting to sell stolen gold.
The Alexandra couple were sentenced last Friday.
The man, who stole more than half a kilogram of gold from his employer, Glass Earth Mining, between September and November 2012, received six months home detention.
His wife, who sold stolen gold on eight different occasions, received four months home detention.
Last year, a 23-year-old man was prosecuted by Central Otago police for stealing ''a few'' grams of gold from his employer.
