It found many statements which made it impossible to tell from the label where the food came from.
The statements included "packed in New Zealand from local and/or imported ingredients" and "made in New Zealand from local and imported ingredients". A few companies had country of origin on some products, but a "vague statement" on others.
In the 10 types of frozen berries surveyed, most were "upfront" about where their berries came from - which included China, Chile, Turkey, Netherlands and Peru.
Sujon Mixed Berries, for example, got raspberries from Chile, boysenberries from New Zealand, blackberries and blueberries from New Zealand and strawberries from Peru, depending on availability.
Michelle Manson of Sujon, a Nelson company, said about 28 per cent of its berries were sourced from Canada and South American companies. She said Sujon's owners had a relationship with farmers going back 16 years.
"The consumer-driven demand for seasonal berries all year round means our New Zealand producers just can't keep up, but we are encouraging them to plant more crops," she said.
Pams boysenberries and Pams raspberries were both labelled as being "packed in New Zealand from local and/or imported ingredients".
A spokeswoman for Foodstuffs, which owns Pams, said various country of origin labels had different and specific meanings. "Packed in New Zealand from local and imported ingredients means the product is packed in New Zealand with either New Zealand or imported produce depending on seasonal availability."
In New Zealand, labelling country of origin is not compulsory, except for with wine, but businesses must not mislead consumers.
According to the Ministry for Primary Industries, the main reason for not adopting mandatory country of origin labelling was the cost involved. "Voluntary use of country of origin labelling, in response to consumer interest, delivers the benefits without imposing additional costs on all consumers or compromising New Zealand's trading interests."
The potential impact of mandatory country of origin labelling hasn't been reviewed by the Government for 10 years. In Australia, it is required on all foods.
To see the full study, visit consumer.org.nz.