"We have worked on this in the past few weeks," U.N. Environment Programme chief Achim Steiner told a news conference on the sidelines of the Copenhagen climate conference on Monday.
"We hope we will have a 100 percent record."
Travel by teams and fans will account for more than 80 percent of the 2010 World Cup's greenhouse gas emissions, UNEP and independent organisation Global Environment Facility said.
"We are a long-haul destination. More than 90 percent of travellers to South Africa will have to use aircraft," Dorah Nteo of South Africa's environment department said.
The carbon footprint from teams' and fan's travels will amount to 1.62 million tonnes of CO2-equivalent and cost $32.5 million to offset, according to preliminary UNEP estimates. The teams will account for an estimated 13,000 tonnes.
Serbia, Uruguay and South Korea have agreed to offset their teams' travel while Argentina, Brazil, Cameroon, Chile, Ivory Coast, England, Greece, Italy, Japan, the Netherlands, New Zealand, Nigeria, the United States, South Africa, Australia and Mexico said they supported the idea and were looking at how to implement it, UNEP said.
Contributing to environment development projects would be one way to do the offsetting, UNEP said.
Steiner said he hoped spectators would also offset their carbon footprint. "My appeal to the fans that will travel to South Africa is: make yourselves part of the solution - then you won't be part of the problem."
The U.N. says greenhouse gas emissions from industry and deforestation will lead to desertification, mudslides, more powerful cyclones, rising sea levels and species extinctions.
