The world's largest floating Christmas tree has been lighted in Rio de Janeiro, marking the official start of the holiday season in the Brazilian city.

The lighting of the tree, which is on a platform in Rodrigo de Freitas lagoon, took place on November 26 amid a fireworks display and the music of the Barra Mansa Symphonic Orchestra.

The tree, officially recognized by Guinness World Records as the largest of its kind in the world, is an 85-meter metal cone that weighs 542 tonnes and is illuminated by 3.3 million Christmas lights.

The floating tree, which has been one of Rio's top Christmas attractions since 1996, is surrounded by 105 km of lighted hoses that produce special effects, projecting images in the sky that are visible for miles, organizers said.

The lighting ceremony also served to unveil the logo of the 2016 Paralympic Games, which will take place two weeks after the Olympic Games end in the South American city.

About 10,000 people turned out to watch the Christmas tree's lighting, organizers said.

The tree, which will be lighted every night until Jan 6, 2012, will be towed to other sites on the lagoon so it can be viewed from different spots in the city.