Police in canton Ticino have launched a major crackdown against cannabis growers and distributors to curb the cross-border trade of the drug between Switzerland and Italy.
Officers confiscated cannabis - much of it destined for Italy - with an estimated street value of about SFr25 million ($18 million).
In a series of raids over the past few weeks, Swiss police seized more than 400 kilogrammes of cannabis and 130,000 plants.
Police said the one of the main aims of "Operation Indoor" was to grab plants grown indoors before they could be moved outside following the onset of warmer weather.
The authorities arrested a number of people and closed eight hemp shops in the canton.
Police revealed that lawyers and financial agents had also been pulled in for questioning in connection with offences including money laundering.
Officers also targeted Italians travelling to canton Ticino to take advantage of Switzerland’s more relaxed attitude to cannabis and the canton’s 75 hemp shops.
In the past five years, the number of hemp shops in the canton has more than quadrupled.
“What we found out during this operation is that people are not just smuggling in small amounts, such as five to ten grams for personal use,” Orlando Gnosca, who heads up the cantonal police drug squad, told swissinfo.
“There are a lot of smugglers bringing in ten, 20 or 50 kilos of marijuana illegally into Italy.”
According to police, many of the smugglers sneak over the border on foot to avoid customs checkpoints at the border.
“They use the old smugglers routes - paths that cross the border - that were used during the second world war for cigarettes, food and illegal immigrants,” added Gnosca.
At present, only hemp with less than 0.3 per cent of tetrahydrocanabinol (THC) - the chemical that gives the "high" when consumed - is permitted under Swiss law.
Police said that the amount of THC in the confiscated plants was on average between ten and 20 per cent.
To date the consumption of cannabis in Switzerland is illegal, but the hemp plant can be grown for non-drug use, for example to make pasta, beer or soap.
A parliamentary commission is currently debating the decriminalisation of cannabis. The Senate has already come out in favour of such a move.
Gnosca said police in Ticino plan to continue the crackdown which was launched in response to public outcry over the burgeoning cannabis trade.
"The Swiss people are pressuring us to do something about this problem," he explained.
swissinfo, Karin Kamp
Swiss police have confiscated over 400 kilogrammes of cannabis and 130,000 plants.
The estimated street value of the drugs seized was about SFr25 million ($18 million).
Most of Ticino's 75 hemp shops are located close to the Italian border.
Some smugglers bring in up to 50 kilogrammes of cannabis illegally into Italy.
Cannabis use is currently illegal in Switzerland, but the authorities have adopted a "tolerant" attitude towards it.
Under Swiss proposals to liberalise cannabis, possession and production of the drug cannabis for personal use would be allowed, as well as a limited trade.
But it would remain illegal to import or export cannabis and advertising would be banned.