The people of Slovenia have overwhelmingly voted against legislation that would grant same-sex couples the right to marry and adopt children.

With over 90% of votes counted in today's referendum, the proposals looks to be defeated by a margin of 63-37.

The country's government has already passed measures affording the rights, but a referendum was called after a group called For Children objected to the legislation in the country's highest court.

While formally registered same-sex couples have many of the same rights as married couples in Slovenia, a bill that would have afforded them the right to adopt children was rejected by voters in 2012.

Despite the clear result, opinion polls in the lead-up to the vote suggest a tight contest.

The government - who support the legislation - did not participate in the referendum campaign, while the main opposition party the Slovenian Democratic Party called for an 'against' vote.

Amnesty International earlier called for the Slovenian people to vote in favour of the legislation, saying "most importantly, this vote is about the couples whose lives will be directly affected by the results".