Sweden's environment minister and deputy prime minister says she will step down from the government after being ousted as co-leader of the crisis-ridden Green Party.

Asa Romson told Swedish news agency TT on Monday she will resign after the environmental group's party congress this week.

Earlier Monday, the Greens announced that they want aid minister Isabella Lovin to replace Romson as one of the party's two leaders at the party congress beginning Thursday.

Education Minister Gustav Fridolin would remain as the party's other leader.

The move comes as the party grapples with allegations that it has been infiltrated by Islamists. The crisis started three weeks when another Green Party member, Mehmet Kaplan, resigned as Housing Minister after Swedish media reported on alleged links to extremists in his native Turkey.