The Green Party is renewing calls for a national register for sites contaminated by toxic chemicals.
A Ministry for the Environment study has found the extent of dioxin contamination at sawmill sites is worse than expected.
The report follows an investigation of 255 sites where the agent pentachlorophenol, or PCP, was used as a treatment of timber in spray or dip form, until its withdrawal in 1988.
A close investigation of 17 sawmills found the level of dioxin contamination was two and a half to five and a half times greater than estimates in the late 1990s.
Green Party co-leader Russel Norman says New Zealanders have a right to know the whereabouts of sites contaminated by dioxin and other chemicals.
