London, England (CNN) -- Movie director, James Cameron has teamed up with environmental campaigners in an effort to help Brazilian tribes' epic fight against the construction of a controversial dam in northern Brazil.

"Defending the Rivers of the Amazon" is a 10-minute interactive presentation created jointly by Amazon Watch and International Rivers and highlights the environmental issues surrounding the building of the Belo Monte dam, in Para state.

Narrated by the actress Sigourney Weaver, the video explains how the dam -- scheduled to be built on the Xingu River, a tributary of the Amazon River -- will flood over 600 square kilometers of agricultural land and rainforest, displacing over 20,000 people who have lived there for generations.

Cameron's help on the project has been invaluable, Amazon Watch's program director, Leila Salazar-Lopez told CNN. The Oscar-winning director helped enlist the services of Weaver and Google Earth.

Earlier this year, Cameron traveled with Amazon Watch to visit tribes living on the affected land. He described the situation as a "kind of 'Avatar' for real"

"I sat in what is essentially a war council circle with a number of these leaders and watched them declare to each other that they're going to fight to the last man, to the last drop of blood, and I think they mean it," Cameron told CNN in April.

In addition to helping produce the Google Earth Animation, Cameron has also released "A Message from Pandora." The three-minute feature premiered the same time as the recent re-release of his 2009 box office hit, "Avatar."

At the end of August, after over 20 years of running into opposition and legal obstacles, the dam was officially given the go-ahead when Brazil's President Luiz Inacio Lula da Silva signed a $17 billion contract with Norte Energia, the consortium chosen to build the dam.

If and when it is completed Belo Monte will be the third largest dam in the world, after the Three Gorges dam in China and the Itaipu dam on the Brazil/Paraguay border.

To counter criticism of the project, the Brazilian government have stipulated Norte Energia spend $800 million offsetting the environmental damage caused by its construction.

When completed the dam will produce 11,000 megawatts and provide electricity for 23 million homes.

But opponents contend that far from solving energy problems, the new dam will create more environmental havoc.

Phillip Fearnside, a research professor at the Department of Ecology at the National Institute for Research in the Amazon, in Manaus, Brazil, believes that the dam's construction, along with another upstream at Babaquara/Altamira, will release carbon dioxide emissions equivalent to those of two million cars over a ten year period.

Aviva Imhof, campaign director at International Rivers told CNN: "In 2005, we produced a book called Tenota Mo -- a comprehensive study of the Belo Monte dam and other projects planned upstream.

"It showed that Belo Monte would not be feasible without additional projects built upstream to store water for release in the dry season."

Imhof added that concerns remain as to how much power the dam will be able to create in the dry season, which is when it is needed most.

A 2009 report compiled by a panel of 40 Brazilian scientists also concluded that the true cost of the project had not been calculated and warned of "serious consequences for the region, its inhabitants, and ecosystems of the Amazon rainforest."

There are alternatives to the dam as Weaver explains in the new video. Imhof says one of them would be to implement energy efficiency measures.

"Studies have shown that the equivalent of 14 Belo Monte's dams could be saved by investing in energy efficiency between now and 2020," Imhof said.

There is also big potential for wind power and solar hot water says Imhof, but she questions whether there is the political will to implement them, given the strength of the hydro lobby in Brazil.

The Belo Monte dam would further increase Brazil's reliance on hydro power -- currently around 80 percent of electricity in the country is produced by it, according to the Pew Center on Global Climate Change.

According to Survival International, a charity supporting tribal people worldwide, say at least seven tribes near the Xingu River are at risk.

But they are determined to continue fighting for their land.

"We must never give up, because we are fighting for a right that is ours!" Raoni Metuktire, a Kayapo Indian said, according to Survival International.

"Nature is life, it has sustained us until today, so we have to defend Nature as our father and mother who give us life....Is this [dam] what we really want, my friends? Let us stand together against Belo Monte!"