Police Minister Judith Collins has congratulated police on shutting down what they allege is a major source of equipment for commercial cannabis growers.

A nationwide drugs bust was executed today, closing down the 16 branches and distribution centre of hydroponic gardening chain Switched On Gardener.

Hundreds of people, ranging in age from 20 to 60, were arrested and will appear before the courts, with many of them facing charges for selling equipment to make secret gardens for growing cannabis.

Police swooped on 35 businesses and homes throughout the country as part of a two-year undercover police operation code named Operation Lime. The operation targeted businesses and individuals commercially selling equipment used for growing cannabis.

Once police knew who was buying the gear, they launched more stings to catch their targets in the act of growing and selling drugs.

Mrs Collins said today's arrests would send a strong message to those who tried to produce drugs in New Zealand that they would be caught.

"The message to those who manufacture and sell drugs in our community is that the Government and the police are determined to shut down your activities, and will use every tool at their disposal to do so," she said.

Directors and managers of Switched On Gardener were among the arrested today and they were due to appear in courts throughout the country on charges which included cultivating cannabis and participating in an organised criminal group.

Police Deputy Commissioner Rob Pope said Operation Lime would "break the cornerstone of the illicit cannabis cultivation industry."

Search warrants were executed in every police district today, he said in a statement.

"Cannabis is the most abused controlled drug in New Zealand. The harm that this drug causes New Zealand communities can be conservatively estimated at $430 million a year. It hurts every community in every part of the country."

During the operation undercover police bought equipment, were given advice on how to grow cannabis, "and even purchased cannabis clones and other drugs over the counter from these offenders."

Mr Pope said businesses had been selling drugs and supporting commercial cannabis growers and organised crime for a long time and the operation had stopped the supply of equipment to grow drugs.

The 250 people arrested face more than 700 charges. They were employees, managers and directors of the companies and growers involved. More than 100 commercial cannabis growing operations linked to the businesses were also raided.

Police said they also seized methamphetamine, LSD, ecstasy and firearms.

Mr Pope said suppliers of illicit equipment to growers would continue to be targeted.

"Criminals buying equipment for their cannabis grows were observed and followed. If people purchase these products for illegal purposes, they can expect to receive a visit from the police.

"Today we are sending a strong message to those who seek to profit from the cannabis industry - you will not get away with it."

Using hydroponic gear to grow fruit and vegetables indoors and under lights was "exceedingly expensive" and it was not a viable proposition, police said. Because of that, the gear was predominantly sold to grow drugs.

Proceedings would also start under the new Criminal Proceeds (Recovery) Act 2009 to seize assets and money but police said honest suppliers of equipment to genuine gardeners were not targeted in the operation.

The online auction site Trade Me today also banned trading in equipment used to cultivate cannabis.