The Springboks' coach, Jake White, was shocked at the severity of the punishment, which was handed out late on Tuesday.
The player said he was contesting the ball when he collided with Polu in the air.
Burger - the 2004 International Rugby Board Player of the Year - will not play again in the World Cup unless his team reach the semi-finals or the ban is overturned.
New Zealand hardman Jerry Collins has warned that it will still be no holds barred despite the tough stance on dangerous tackles.
One of the toughest defenders around, he said that being cited for a rash tackle did not play on his mind during the 80 minutes.
'It's a lottery whether you're going to get a referee who's pedantic or you're going to get a referee who's going to enjoy the weather and the free-flowing rugby and let it go.
'We're aware that it can be the end of your tournament and they're coming down pretty hard on indiscretions.
'But, if the game's brutal, these things happen. It's a part of life.'
REUTERS