Stoejberg recommended informing on food businesses on Wednesday after Danish media reported that a growing number of people were living in Denmark illegally.

The minister said she "actually would encourage" ordinary Danes to contact the authorities if they notice something strange in their local pizzerias, such as many employees "not speaking Danish at all."

The authorities still carry the biggest responsibility for finding illegal immigrants, she also told Denmark's TV2 channel. However, it was "utopian" to believe that the police can check "every back room in Denmark."

Stoejberg's comments prompted a response on Danish social media, with users "informing" their friends of the best pizzerias in their neighborhood.

Taking the cake

The hardline minister is no stranger to controversy. Two weeks ago, she sparked outrage by posting a picture of herself with a cake commemorating the 50th government measure to tighten immigration law.

She was also involved in the push to seize immigrants' valuables and jewelry in order to pay for their stay in immigration centers.

According to Danish media, the number of foreigners living illegally in the Scandinavian country has risen from 877 people in 2015 to 1,348 last year. The state, with its population of 5.6 million, has been mostly spared from the immigration wave that hit Germany and Sweden.

Illegal immigrants in Denmark often live in miserable conditions, according to Copenhagen's police inspector Kjeld Farcinsen, as cited by the Danish mass-circulation newspaper "Ekstrabladet."

The migrants work for very low wages, typically between 2,000 and 4,000 crowns per month (around 270 euros and 540 euros), he told TV2.