Television New Zealand has apologised for a technical glitch during its Olympics coverage on Wednesday afternoon, but says it cannot guarantee it will not happen again.
Many viewers missed out on the final of the men's 200 metres butterfly, in which New Zealander Moss Burmester finished fourth.
The gold went to American Michael Phelps, who has now won five golds at the Beijing Games.
TVNZ says a switching failure at its headquarters in Auckland affected viewers receiving the broadcast via satellite - either through Sky or on Freeview - along with viewers with analog transmission in the South Island.
It says such problems are one of the hazards of broadcasting in a complex technical environment.