Italy's lower house of parliament was set to start a final debate Monday on a bill which, if approved, should end Italy's status as the last Western European nation not allowing gay unions.
Italy has been under pressure from bodies like its constitutional court and the European Court of Human Rights to change the status quo. However, past reforms attempts have been stymied by the Catholic Church and conservative politicians.
"By Wednesday or Thursday, Italy will have a law," Prime Minister Matteo Renzi, who is a centre-left Catholic, said in a late Sunday interview with RAI state television.
"I think it will be a good thing for everybody, not just for homosexuals," he added.
Renzi said the government would call a vote of confidence over the issue in order to speed through the approval. "I feel very confident that this thing will pass," the premier said.
The law grants same-sex couples similar rights to married ones in terms of inheritance, housing and pension rights and hospital visits, and also allows them to take on the same surname.
It originally included a so-called stepchild adoption clause, allowing gay persons to adopt the children of their partners, but it was excised on the insistence of centrists in the ruling coalition.
The final compromise disappointed gay rights activists, but still represents a major reform for a country with a traditionally conservative approach to family affairs.
In January the debate prompted pro- and anti-reform rallies, each claiming attendance figures of more than 1 million. Catholic groups mobilized against the bill, but won no direct endorsement from Pope Francis. The Catholic church is traditionally opposed to efforts legalizing gay marriage.