A recent Consumer NZ investigation of 20 extra-virgin olive oils revealed that some oils labelled as New Zealand also contain imported oils.

'Most oils state the origin of the olives or oil, but not all are upfront, and you could be forgiven for thinking some New Zealand olive oils are made from 100 percent New Zealand olives,”, says Consumer NZ research writer Belinda Castles.

Despite Matapiro New Zealand 100% Extra-Virgin Olive Oil and Village Press First Press Extra-Virgin Olive Oil stating New Zealand on the front label, there's no mention where the olives or oil comes from.

Matapiro says its oil is blended with Australian olive oil to meet demand. The company is hoping to return to wholly New Zealand grown olives and oil soon.

Village Press says its First Press blend is typically New Zealand extra-virgin oil blended with Australian oil. The company told Consumer NZ the reference to New Zealand represents that it is a local business where all oil is blended, filtered, bottled and labelled within the country.

Village Press tells Consumer NZ the label will be amended at its next harvest so it's clear not all the First Press oil is New Zealand sourced.

New country of origin regulations, which come into force for fresh food from February 12 2022, make it mandatory for companies to disclose the origin of certain foods such as fruit and vegetables, meat and cured pork, and fish and shellfish. Olive oil is not covered by the regulations.

Consumer NZ is asking for regulations to include all single ingredient foods and olive oil falls into this category.

Consumer NZ olive oil results

Consumer NZ tested 20 extra-virgin olive oils from New Zealand, Australia, Africa, and Europe. All oils met the criteria to be labelled extra-virgin and two Kiwi oils achieved gold medal standard (86 to 100 per cent) in the blind tasting carried out by accredited tasters.

What to look for when buying olive oil

• Buy the freshest oil possible. Look for a pressed-on or harvest date. Best-before dates aren't always a good indicator of quality, as you don't know how old the oil can be.

• Green or dark bottles, or tins, provide better protection from the light. Don't buy clear-bottled oils, especially ones that have been displayed in a shop window or under fluorescent light.

• Store in a cool dark place, tightly stoppered.

• Don't stockpile. Oils don't improve with age so use any open oil within 12 months.