EarthX founder Trammell S. Crow, of Dallas, runs the world's largest environmental sustainability expo and has given the university $250,000 for the build.
Mr Crow visited the university three years ago and was impressed by the work it was doing on climate change and weather volatility, and the work of Prof Gary Wilson to develop the university's marine science research.
"We've been following Gary for a couple of years now," Mr Crow said.
"He's extremely active and dedicated to his research on the environment, specifically climate change, carbon dioxide and sea levels in the Antarctic and the Southern Ocean."
Mr Crow said that Prof Wilson was "highly committed to his work" and the $250,000 investment was made in the hope others would follow his example.
"Otago is New Zealand's pre-eminent research university, and considering the underlying growth in students wishing to study marine science and climate change, a dedicated faculty needs world-class training facilities."
"The Polaris II is an older wooden vessel and it needs replacing as research challenges and teaching needs grow.
"Globally, there has never been a more important time for marine research.
"Our research requires greater technical capability and our teaching requires on-the-water training across a range of environments with improved technologies."
He said the university had committed initial funding of $500,000 for a new research vessel, and was seeking additional support through a fundraising campaign.
It was hoped the replacement vessel would have a faster cruising speed, room to accommodate 20 people, stronger construction in steel or aluminium, more deck space to allow for special-purpose containerised labs and a low acoustic signature to minimise disturbance and help acoustic research.