Copenhagen: Denmark has become the third Nordic country this year to form a leftist government after Social Democratic leader Mette Frederiksen finalised terms for a one-party minority government.

A bloc of five left-leaning opposition parties led by the 41-year-old's Social Democratic Party won a majority in a June 5 election, prompting centre-right leader Lars Lokke Rasmussen to resign as prime minister.

Danish Social Democrats chairman Mette Frederiksen. Credit:AP

"It is with great pleasure I can announce that after three weeks of negotiations, we have a majority to form a new government," Frederiksen said.

She will have to rely on the Socialist People's Party, the Red-Green Alliance and the Social-Liberal Party - formerly headed by European Competition Commissioner Margrethe Vestager - to pass laws in the 179-seat parliament.