'Avatar' director James Cameron urged young Americans Monday to pursue careers in science and technology to keep the United States at the forefront of technical innovation - and allow him to make more blockbuster movies.

Science, technology, engineering and mathematics, or STEM, "are where this country has to continue to lead," Cameron said at the US finals of the 8th Microsoft Imagine Cup, where students presented projects they developed that use technology to fight global problems.

"We can't fall behind in that area. We need engineers, we need innovators," Cameron said, adding that 'Avatar' would not have made it into cinemas without innovative technology developed by Microsoft and the out-of-the-box thinking of a young team, average age 23, who put the technology to work in the movie.

The Imagine Cup aims to inspire young people to use their talents and technology to do everything from making movies to saving the planet, Microsoft chief research and strategy officer Craig Mundie said.

"Whether you're trying to make Avatar or trying to solve the carbon problem in the atmosphere you want to have powerful teams enabled by these technological tools," Mundie said.

Cup participants have to develop projects that use technology to make a difference in the lives of people in their local communities and around the world, addressing issues of education, healthcare and environmental sustainability.

Eighty students out of a starting field of 22,000 made it to the US finals of the competition with projects that dealt with everything from pollution to pediatric illness to poverty.

The winner of the software division - a project called Mobilife, by students at the University of California, Davis - will travel to Poland in July to compete against teams from more than 150 nations in the world finals of the Imagine Cup.

Mobilife uses the Windows Mobile platform and computer-assisted microscopy to allow doctors who work without the benefit of the facilities of a modern hospital - such as field doctors in sub-Saharan Africa - to detect vascular diseases in children, including diabetes, hypertension and sickle cell anemia.

The game design division was won by a game called "Sixth", which raises awareness of global poverty by putting players into the skin of a child in a slum in India who has to battle his way past obstacles to collect water for his family.

"Sixth" was developed by students at the two-year Central Piedmont Community College (CPCC) in North Carolina, who beat out academic big hitters like Ivy League university Yale to take top honors in their division.

Cameron singled out "Sixth" - the name refers to the sixth of the world's population that lives in poverty - for praise, saying it "puts the player into another human being's reality and triggers a compassionate response and a call for action."

Avatar aims to do the same, but with a message about saving a planet that is being destroyed by unchecked development and human greed.

Imagine Cup competitors are to Earth what the nature-loving Na'Vi and their human avatar allies were to the planet Pandora, said Cameron.

"These young leaders are so inspirational, they are going to be the warriors for the Earth and are going to save us," he said.

Will Isenhour, a 33-year-old graphic artist who is studying game design part-time at CPCC, was part of the team that created "Sixth".

"James Cameron specifically gave us the nod," he told AFP.

"I'll have to put this on my resume and drop him a line.

"I have a pretty crappy job right now so if anybody's hiring, I'm available," he said.