The Evangelical Lutheran Church in Finland has announced that it will not officiate same-sex weddings as the country's gay marriage law takes effect in March next year.

At a bishops' meeting held in Joensuu on Wednesday, it was decided that the church will only officiate the weddings of heterosexual couples.

An 11-page proclamation said the parties to a church wedding should be a man and a woman, according to Yle.

Same-sex couples can register their partnerships and have civil weddings at local registry offices.

"The church is not turning its back on sexual and gender minorities or rainbow families, but they are welcome in all other respects. They are a part of us, and not separate from us or some kind of problem," said Archbishop Kari Mäkinen.

Lawmakers voted in November 2014 to legalise same-sex marriage, a move that was lauded by Mäkinen. The archbishop's reaction led to about 3,000 members quitting the church.

"The change to marriage laws means that members of the Finnish Evangelical Lutheran Church, persons in high office and workers stand with same-sex [persons] in marriage," according to the bishops' announcement.

Mäkinen said the church's official line on same-sex marriage may have disappointed people.

"I can imagine that there must have been some expectations that something definitive would happen now," he said.

Mäkinen did not say what action the church will take if a cleric breaks the church guidelines and officiate same-sex weddings.

"At this stage it is not possible to say what the consequences of such an action would be," he said.

The bill to legalise same-sex marriage in Finland was approved by the president in February last year. Laws were changed to reflect such in social benefits and healthcare.

The bishops' announcement also said that a priest can pray for and with persons who have gotten married in a civil ceremony.