OLIVE oil consumers continue to be duped as testing shows more than 80 per cent of imported "extra virgin" oils are pretenders.

Testing conducted by independent laboratory Modern Olives shows most imported oils labelled as premium "extra virgin" do not live up to the standard - some samples showed other oils had been partially substituted.

The news comes just two weeks after the Australian Competition and Consumer Commission ordered three imported oils to provide tests to prove their "extra virgin" status for the next three years, following the discovery they were imposters.

The recent results - in which Australian oils performed well and imported oils were found to be largely bogus - mirror the results of Modern Olives' annual testing for the past two years.

Australia has no lawful standard which defines "extra virgin" and critics say this has made Australia the world's dumping ground for poor-quality oil falsely labelled as extra virgin.

Modern Olives scientist and oil expert Claudia Guillaume said statistics showed there was less extra virgin olive oil produced in the world than consumed, meaning some had to be wrongly labelled.

"Some samples in our testing were old ... the rest had been refined or had heat treatment and a few (had other oils added)," Ms Guillaume said.

Heat treatment, which lowers the product to the "virgin" standard rather than "extra virgin", was used to deal with oxidation, acidity and bad smells, she said.

Test results had not improved following widespread media exposure and the ACCC's investigation into the issue.

Australian Olive Association president Paul Miller said he expected "a lift in quality" of olive oil following the ACCC's issue of testing orders. He was "impressed" with the ACCC's action, although believed offenders should be issued with fines as well as orders to provide tests of their oil.

"We would like the Australian standard to be law ... that would make life easier for (the ACCC)," he said.

He applauded Aldi for being the first Australian supermarket to require suppliers prove to their oil labels.