Coillte has rejected claims by the Green Party MEP, Ms Particia McKenna, that it is using a banned pesticide on its plantations.
Earlier today Ms McKenna condemned the state forestry board for its use of Permethrin, a pesticide used in the control of pine weevil - an insect which attacks trees.
She says Permethrin is a "toxic carcinogenic substance" which has been banned by the European Commission since December 2000.
She said: "It is completely irresponsible and unacceptable behaviour on the part of the Irish authorities."
"This substance is carcinogenic, it can pollute the water supplies and enter the food chain via the soil. The Government is therefore placing Irish people at risk by supporting its continued use," she added.
However a spokeswoman for Coillte said Permethrin "is not a banned substance for use in forestry". She said the EU is permitting the use of the chemical "in young plants for forestry" until July 2003 at which point it will be phased out.
She said Coillte was fully compliant with the December 2000 EU directive and that use of chemical would be discontinued after the recommended date.
She also said a report by the EU Standing Committee on plant health found no evidence that Permethrin was carcinogenic or that it posed a danger to human health.
Ms McKenna told ireland.com this afternoon that the World Health Organisation had defined Permethrin as "a possible carcinogenic" and that the Pesticide Action Network had described it as "acutely toxic" when found in an aquatic environment.
She said the Irish authorities were simply looking for a derogation to continue using a substance which has been banned or is being phased out of use because of its toxicity.
She said Coillte was acting "irresponsibly".
