Legalising cannabis production would have benefits for public health and human rights, according to a study commissioned by Dutch local authorities.

The 27 municipalities are among a group campaigning for a change in the law that would allow them to regulate the growing and wholesale of weed plants. The government has rejected such calls for years, arguing that it would breach international treaties designed to restrict the illegal drug trade.

The study by Radboud University in Nijmegen found that illegal cannabis production was linked to criminal violence, fires, environmental and noise pollution and the spread of legionella bacteria, the Volkskrant reported.

Legalising the process, they argued, would potentially improve health and safety and therefore be justified on human rights grounds. Local authorities would have more scope to reduce the harmful effects of cannabis, for example by limiting the level of the active ingredient THC in legally grown plants.

They added that the government would have to guarantee that any measure did not affect the situation in other countries, so any legal cultivation would have to be tightly regulated with a total ban on exports.

The legal status of cannabis production has been a long-running political sore point. So-called ‘coffeeshops’ are permitted to sell small quantities of the drug under licensed conditions, but the wholesale trade remains illegal, meaning the cafes have to buy their supplies on the black market.

The Radboud researchers stressed they were not passing judgment on the current policy, but wanted to challenge the government’s long-standing argument that international law blocked any moves towards legal cultivation.

International law professor Geert-Jan Knoops told the Volkskrant that the government was worried about setting a precedent. ‘The argument is that the ban should be lifted because of the negative effect of a ban. That would mean that the same logic could be applied to other things that are currently illegal,’ he said.