Santiago (AFP) - Chile's Congress on Wednesday approved the country's first law authorizing civil unions of gay and lesbian couples.

The law, which has been in the works for four years, gives legal recognition to unmarried couples and ensures their rights to receive pensions, enroll in health plans and inherit property from one another.

It also gives them greater standing in child custody cases.

"We are happy that the state recognizes, for the first time, that a same-sex couple also is a family and deserves protection," said Luis Larrain, head of the Fundacion Iguales, a gay rights group.

Once signed into law by President Michelle Bachelet, the measure must past muster with Chile's Constitutional Court before going into effect.

Gay marriage has been recognized in Argentina, Uruguay and Brazil. Colombia and Ecuador recognize civil unions or partnerships of same-sex couples.

Chile, a conservative country with a Roman Catholic majority, has been slower to change.

It was one of the last western countries to pass laws, in 2004, recognizing divorce. Abortion for any reason remains banned, and sodomy was punishable with prison until 1999.