Harinordoquy helped France win the Grand Slam in 2010 and also steered his club side, Biarritz Olympique, into the Heineken Cup final against Toulouse in Paris.
The other nominees are the 2009 winner, Richie McCaw, his All Blacks team mate Mils Muliaina and new South African cap record holder Victor Matfield. The winner, along with the IRB Coach of the Year and IRB Team of the Year, will be announced on 1 December.
"The six players nominated have all enjoyed an exceptional year of international Rugby and have been judged on their performances in the RBS 6 Nations, Tri Nations, June and November Tests," said IRB Chairman Bernard Lapasset.
"It is an impressive shortlist. Richie McCaw has already made history as the first player to win the Award twice, while Imanol Harinordoquy, Victor Matfield and Mils Muliaina have consistently performed to highest standards over the years.
"It is also pleasing to see some of the brightest stars of the world Game in Kurtley Beale and David Pocock also nominated for their achievements during what has been a fascinating year"
IRB Player of the Year Award Winners
2009 - Richie McCaw (New Zealand)
2008 - Shane Williams (Wales)
2007 - Bryan Habana (South Africa)
2006 - Richie McCaw (New Zealand)
2005 - Dan Carter (New Zealand)
2004 - Schalk Burger (South Africa)
2003 - Jonny Wilkinson (England)
2002 - Fabien Galthie (France)
2001 - Keith Wood (Ireland)