The owner of a Tauranga based company selling volcanic rock being investigated by the Commerce Commission says the company has done nothing wrong.

John Morris, owner of Agrissentials in Te Puna, says if the Commerce Commission had a case against the fertiliser company they would have acted by now.

The Commerce Commission has been investigating the company under the Fair Trading Act since January this year.

'I rang the commission this morning and was told they had not yet made a decision about taking action over the complaint they had received.”

John says he is unsure what the complaint is based on or who made it, other than it related to a newspaper article.

'We were asked a series of questions by the commission to which we have responded.”

Agrissentials produces a range of fertilisers including Rok Solid, which it describes as a BioGro-certified blend of essential minerals and trace elements in powdered form, containing more than 63 minerals.

Commerce Commission spokeswoman Allanah Kalafatelis says an investigation was started earlier this year after a complaint was received from a user of the fertiliser.

'The investigation is under the Fair Trading Act, which prohibits misleading and false claims by traders.

"We don't expect it to be a short investigation because of the science involved. There's a small number of experts we can go to."

John says the complaint may have arisen because of what appeared to be a discrepancy between the labelling on Rok Solid and claims made in the newspaper article.

'We list 19 essential elements on our labelling but know there are more than 63 because we use fish and kelp in the product.”

The company's fertilisers are not soluble and don't leach into water ways.

'Products like super phosphate are extremely soluble and that's a real problem for the environment.”

John doesn't see publicity about the commerce commission investigation as bad for his company.

'It's been reported up and down the country which means more people know about us and if it sparks more discussion about fertiliser use and the environment, then that's good.”