Drug seizures in Skåne have dropped by 16 percent this year compared to 2012.
The reason is dissatisfaction among customs staff, according to Jan Martinsson, chairman of the Tull-Kust trade union which represents workers in Swedish Customs (Tullverket) and the Swedish Coast Guard (Kustbevakningen).
"We're not being super successful in our work every day, if you see what I mean," Martinsson told the TT news agency.
"Customs officers have to be hungry to go after the loot. If you're not hungry, if you are dissatisfied - well, then these are the consequences".
Martinsson stressed that the union is not behind the customs officers' protest, but is aware of their tactics.
"I know that there is widespread dissatisfaction among my members," he said.
Martinsson explained that a thinning workforce means customs officers cannot keep up the same high standards as usual.
But Michael Nelander, head of crime prevention at Swedish Customs in the Skåne and Blekinge regions, claimed that he has not noticed a decrease in work efficiency.
"I don't want to believe that it's true - that our staff members, who are very professional, responsible and passionate about their work, would take that kind of measure. I have a very hard time believing that," said Nelander.
He called slowdown tactics "unacceptable".
However, one customs officer confirmed that around 150 staff members in Skåne are participating in the protest, which involves cutting down on random inspections.
"In general, we are dissatisfied with the situation", the customs officer, who wished to be anonymous, told TT.
"There are too few of us. It has been a turbulent time with changing work hours and so on… We feel you have to put your foot down."
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