Wesley is a decile two college and the school which produced rugby legend Jonah Lomu, who was head prefect and captain of the 1st XV in 1993.
Also, eight men who represent Fiji, Tonga and Samoa in this year's World Cup were Wesley old boys - including Samoan No 8 George Stowers.
The St Bede's student who led the debate, who does not play in the school's 1st XV, said, "Nigs can't think".
"They are s*** at rugby after school because club footy requires more than just being big and black and being fully developed at the age of 15," he wrote.
Pete Malcouronne, author of Our Game - a book about rugby and race relations - was shocked by the comments and laid a complaint with the Human Rights Commission.
Malcouronne said racism was rugby's dirty secret, despite some of New Zealand's top players coming from Polynesian backgrounds, including Tana Umaga and Ma'a Nonu. The complaint is being assessed.
Manu Samoa media manager Fatu Tauafiafi said the comments "belonged in the rubbish" but said he had heard that kind of thing before. He said some Samoan players had their own businesses and some planned on moving to academic careers after retiring from the code. "People like us who receive those comments know rightly where it belongs - in the rubbish," Tauafiafi said.
St Bede's rector Justin Boyle said he would consider sanctions for the students.
"I'm bitterly disappointed that seven or eight students here associated with the college should descend to that level and unfortunately give the place a bad name, because it's certainly not reflective of most of the boys at this college," Boyle said.
Only two of the students involved played in the 1st XV.
Most of the team - including a Tongan, five Samoans and four Maori - lost graciously to Wesley College, he said.
"Some of the boys who are Maori and Samoan are also very good academics and, if they looked a wee bit closer instead of shooting off their mouths at their own people representing them in 1st XV, they would know these guys are not just rugby players but also highly intelligent and good kids in the classroom."
Boyle said he would speak to the students and their parents before deciding whether formal discipline was necessary.