A Stirling North couple who sold cars while unlicensed have been fined a total of $6000.

Last month, 42-year-old John Phillip Skrlj and 51-year-old Katrina Lee McKerlie appeared in the Port Augusta Magistrates Court, and pleaded guilty to charges of dealing in vehicles without a licence.

The court heard that Consumer and Business Services has previously warned Skrlj after he had bought, sold or offered for sale eight vehicles over a 12 month period without a second hand vehicle dealer's licence.

As a result, he entered into an assurance with the Commissioner for Consumer Affairs, committing not to sell any more vehicles without a licence.

The court was told that the following year, CBS received a complaint that Skrlj had still been selling vehicles through social media.

A subsequent investigation revealed that Skrlj and his partner were still selling vehicles, with the couple selling a total of nine vehicles over the course of 12 months.

"This is a serious matter - Skrlj knew the law, had been warned he was breaking it, yet continued offending," Commissioner for Consumer Affairs Dini Soulio said.

Skrlj was fined $3600 while McKerlie was fined $2400.