Interviewed by the Church of Sweden's newspaper Kyrkans Tidning, the Social Democrat prime minister compared priests who refuse to wed same-sex couples with midwives refusing to carry out abortions.
"Us Social Democrats work to ensure that all priests should wed all people, including same-sex couples. If you are a midwife you either have to carry out abortions, or you have to find another profession. The same goes for priests who do not want to wed homosexuals," Löfven told the paper.
Same-sex couples in Sweden have been legally entitled to wed in church since May 2009, although individual priests can choose whether or not they want to perform such services. Church of Sweden priests also have the right to decline to any other services, including baptisms, funerals and weddings.
The Church has, however, taken an active stance on gay weddings that goes further than the legislation, and actively endorses same-sex marriage.
Löfven, who is not religious himself, backs bills that have been submitted to the Church of Sweden's decision-making body, Kyrkomötet, about making willingness to wed same-sex couple a prerequisite for ordination.
"I can understand that people can have difficulties getting to terms with this for faith reasons, but as an open democratic church, the church is an organisation that stands for equal rights of all people. People who love each other, regardless of their sex, should have the same right to marriage," Löfven said.