Fonterra's ad for Tamar Valley yoghurt described the product as "made in Tasmania, exported to Australia".

A complaint from a member of the public to the board said: "Tell us which and what ingredients are local, probably most of the time the most minute ingredient such as a drop of water is the local ingredient".

The Ad Standards Board vindicated the complainant with an acknowledgement the berries in the product were imported.

It noted that the yoghurt was made in the Tamar Valley from Tasmanian milk.

A Fonterra spokeswoman said the company accepted the findings and would not show the ad in that format again.

"At Tamar Valley Dairy, creating quality dairy foods and buying local is a priority and vital to the community," she said.

"One hundred per cent of the milk used to make Tamar Valley Dairy yoghurt is sourced from our local Tasmanian dairy farmers, who produce high-quality fresh milk year round.

"It's important to us to source locally where it is possible, however, unfortunately in the case of berries there is no consistent, year-round berry supply in Australia. To ensure we're making yoghurt all year round, at a competitive price, we need to source our berry ingredients via an accredited supplier from a number of countries."