Television New Zealand says the 2008 Beijing Olympics may have been the last people can watch without paying for a subscription.
Sky Television has secured the New Zealand broadcasting rights for the 2010 Winter Olympics in Vancouver and the 2012 Summer Games in London.
TVNZ chief executive Rick Ellis says Sky TV securing the rights may result in a large number of households being locked out of viewing the event in London.
Mr Ellis New Zealand does not have any regulatory framework to protect against universal access to free sport, which means the highest bidder for such events wins.
Sky TV declined to comment on speculation over its planned Olympic coverage.
However, it has said it will offer 24-hour-a-day coverage during the Games, on its subscription channels and on Prime, which is free to watch.
Despite record viewing numbers for the Olympics, TVNZ says it will make a multimillion-dollar loss on its Games coverage. The state-owned broadcaster says 96% of the population tuned in to some of its Olympics programming.