The Environment Ministry said the shipments were seized on October 4, as well as November 1 and 16. The shipments totaled to 22.82 tons of plastic waste, which was prevented from reaching Latvia.
The ministry claimed the responsible persons had planned to pass the waste off as collected in Latvia and to recycle it in the country to receive tax rebates.
The State Environmental Service has carried out 46 checks in international waste shipments and just these three violations have been uncovered.
Outgoing Environment Minister Kaspars Gerhards (National Alliance) said that new laws have increased the authorities' ability to control waste shipments.
"I think that the illegal shipments we've stopped are a clear signal that Latvia is not and will not be a destination for illegal waste," he said.
Norwegian and Swedish authorities have been informed about the cases. An investigation is to be started based on the findings.
Last year a huge fire of waste stored in an illegal dump and imported from Sweden erupted in Jūrmala, prompting an apology from the Swedish Environment Minister.