The Commerce Commission and health officials are investigating whether a church group's claims that it has a cure for Ebola are misleading and illegal.
Genesis II Church's co-founder, Mark Grenon, is in the country to promote the product, known as Miracle Mineral Solution, which he said could also cure AIDS, cancer and malaria.
The Commerce Commission said it would carry out an initial assessment into whether the claims breached the Fair Trading Act.
The Government's medicine's agency had already warned that the product was unsafe.
Medsafe said it had also provided a clear warning to the company operating the website used to sell Miracle Mineral Solution that it might be breaching the medicines act.