"The elk start migrating every December, searching for better grazing areas near the coast," Lars Lundman of the Norrbotten police told the Dagens Nyheter newspaper.
"And hunters and forest workers have reported seeing an unusual amount of them this year."
He said that groups of up to 20 elk had been sighted on the move at once.
"The elk start migrating before the snow gets too deep," he added, suggesting that frozen tree shoots could have been a catalyst in their migration.
Police have warned local motorists and travelling Swedes alike to take heed on the E10, the E45, the 373 and Silvervägen. Officers said drivers should take particular caution if they spot animals by the roadside.
Elk are one of the top causes of traffic accidents in Sweden, with over 4,700 incidents reported so far in 2014 alone.