Methyl bromide should be banned because of evidence exposure to the chemical increases the risk of developing motor neuron disease, the Council of Trade Unions (CTU) says.
The chemical, used for the pre-export fumigation of logs, had been linked to the deaths of six Port of Nelson workers from motor neuron disease.
The Nelson port population suffered a rate of motor neuron disease 25 times the international average, the CTU said.
CTU president Helen Kelly said humans should not be exposed to the chemical, which also had a damaging effect on the ozone layer.
The European Parliament had banned the use of the chemical from March this year, and New Zealand should follow its lead, Ms Kelly said.
China, Japan, Malaysia and Korea were among New Zealand's major log importers and all would accept timber fumigated with phosphine instead of methyl bromide, she said.
