Cubans have approved a sweeping "family law" code that will allow same-sex couples to marry and adopt as well as redefining rights for children and grandparents, officials said on Monday, though opposition in the national referendum was unusually strong on the Communist Party-governed island.

The measure " which contains more than 400 articles " was approved by 66.9 per cent to 33.1 per cent, the president of the National Electoral Council, Alina Balseiro Gutierrez, told official news media, though returns from a few places remained to be counted.