Concerns a chemical in some weedkiller products could have harmful effects on foetal development

The Environmental Protection Authority's heavily restricting the use of chlorthal-dimethyl - also known as DCPA.

The United States banned the substance in August - following research findings that exposure to fields treated with the chemical - could affect the hormones of unborn children.

The EPA says the chemical isn't widely used in New Zealand.

It's temporarily restricted its use under the Hazardous Substances and New Organisms Act - while a review is undertaken.

A ban of the substance may follow.