Nigeria's health minister says Covid-Organics - a herbal tonic produced in Madagascar and touted as a cure for coronavirus - has ingredients used for malaria treatment, but the government is still probing its effectiveness for COVID-19.

Osagie Ehanire said that preliminary results of analysis by the National Institute for Pharmaceutical Research and Development (NIPRD) confirmed it contained artemisia, a plant used in malaria treatment.

"Further research on its efficacy will be conducted when the grants for research is approve," the minister is quoted by Nigeria's Premium Times as saying.

The World Health Organization (WHO) has warned against using untested remedies for coronavirus.

Madagascar's President Andry Rajoelina has been promoting the herbal tonic across the continent.

At its launch it was revealed it had artemisia and other Malagasy plants.