The senate has written to justice minister Ivo Opstelten summoning him to explain what he is doing to deal with the problem of illegal marijuana production in the Netherlands.

Opstelten and home affairs minister Ronald Plasterk will be grilled by senators in September about the grey area between sanctioned sales in cannabis cafes and the supply side.

In the letter from the senate’s justice committee, senators state that Opstelten has not changed his position, despite being urged to do so by over half of the country’s mayors.

Good government

The senate is of the opinion that good government should listen to local government, the letter reads.

‘A large group of mayors are worried that more people are becoming involved in growing marijuana and coming under the control of organised crime,’ the letter says before stating senators want to know what concrete steps the minister is taking to solve the problem.

Opstelten has said several times he will not begin experiments with regulated marijuana production.

At the moment it is illegal to grow marijuana. This means there is a grey area between the official policy of turning a blind eye towards possessing small amounts of marijuana and the supply to cannabis cafes, known as coffee shops.

Labour senators said last month they want to sanction regulated marijuana production trials.