In previous years around 10 percent of all new recruits have had non-Swedish roots. But in the two latest application cycles, the figure was halved to five percent, Swedish Radio's news programme Ekot reported on Friday.
“I have been here since we started in 2001 and we have had some groups where we've reached almost 15 percent,” said Betty Rohdin, head of education at Växjö police academy in southern Sweden.
“When you had international visitors you could send round an email asking 'can anyone help me interpret to Arabic?' and you got seven responses. Nowadays there is hardly anyone who can help,” she added.
Around 16 percent of Sweden's total population is from a foreign background. And representatives from the police union believe a force with mixed ethnicities is essential to ensure the rule of law.
“That a police force in a state that honours the judicial system reflects the ethnic composition of its citizens, I think that is something that should be a matter of course,” Christer Palmkvist told Ekot.
It is unclear what has caused the sharp decline, but the police union puts it down to a recent change in the application process, which sees admission offices focus more on high school grades instead of personal interviews.
Police tell Ekot that more officers from a non-Swedish background are needed partly for communication reasons in some of the bigger cities' troubled suburbs where there is a high number of residents from immigrant backgrounds.
In southern Sweden, after a summer of violence, Malmö police announced last month that they were stepping up their presence in known trouble-hit areas such as Rosengård and Seved, areas with a high presence of often race-related violence between different ethnic groups.
But although nobody wants to say it outright, a dark shadow of previous racism accusations against Swedish police also looms.
During another spell of unrest in Rosengård some five years ago, three Skåne police officers were recorded on video making racist and threatening comments about residents in the area.
The police dialogue in the film caused a great deal of debate in Swedish media and soul searching within the Swedish police at the time.