OSLO (Reuters) - A Swedish appeals court upheld on Thursday a dismissal of Tesla's lawsuit against Sweden's Transport Agency in a conflict over licence plates, part of a wider dispute between the U.S. company and labour unions in the Nordic country.

The electric vehicle maker faces a wave of union action in the Nordic region, backing Swedish IF Metall's mechanics who have been on strike since last year, demanding a collective agreement covering wages and other conditions.

The unions have, among other things, prevented Tesla from importing cars via Swedish ports, and have launched a postal blockade to make access to licence plates for new vehicles more difficult.

Tesla had sued the Transport Agency to demand that it ensures access to the plates needed.

"The Court of Appeal agrees with the District Court's assessment that the general court ... does not have jurisdiction to hear the action brought by Tesla," the Gota court said in a statement.