Correction: Thursday, February 25th, 2016: This article originally quoted Iva Spoljar Saric as saying she thought traditional marriage is in jeopardy from homosexuals. In fact, she said traditional marriage is not in jeopardy from homosexuals in Croatia's same-sex marriage vote. She is not a member of the "In the Name of the Family" group. We apologise for these errors”

Gay rights supporters have staged protests in Croatia ahead of a controversial referendum that could outlaw same-sex marriage in the EU's newest member state.

More than 1,000 demonstrators marched through the streets of Zagreb on the eve of Sunday's vote on whether to amend the country's constitution to define marriage as a "union between a woman and a man".

"With this sentence in the constitution we would make the lives of our fellow citizens, who are a sexual minority, more difficult," warned Damir Kovacic, who took part in Saturday's protest with his wife.

"And tomorrow a referendum about someone else's rights might be on the agenda," the 34-year-old electrical engineer told the AFP news agency.

The referendum in the staunchly Catholic country had to be scheduled after a campaign by a group called In the Name of the Family gathered over 750,000 signatures in favour of the vote, despite strong opposition by the country's centre-left government and numerous human rights activists.

The group insisted that traditional marriage, moral values and children were in jeopardy from homosexuals.

"Nothing will change anyway. Everything is already defined by family law," said Iva Spoljar Saric who is married with children.

"I personally think that traditional marriage is not in jeopardy from homosexuals," she added.

'Yes' vote likely

The latest survey showed that 68 percent of Croatians on Sunday would vote "yes" compared with 27 percent against.

Attitudes towards gay rights have slowly been improving since Croatia's first Gay Pride parade was held in Zagreb in 2002, when dozens of participants were beaten up by extremists.

Pride parades are now staged regularly, if still under strong security, while gay rights are more openly discussed in the media and people are becoming less fearful of "coming out".

In 2003 Croatia adopted a law recognising same-sex couples who have lived together for at least three years. Yet apart from official acknowledgement, the measure granted them few rights.