Spark is telling customers it's "too early to say" if the streaming issues which plagued Saturday night's All Blacks match will be resolved in time for Sunday's matches.
"Unless we confident of this, then we will look to simulcast tonight's matches on TVNZ DUKE to ensure New Zealanders have a good viewing experience," a spokesperson for Spark said on Sunday morning.
"We intend to make a decision on whether or not to simulcast by 1pm today [Sunday], to ensure our customers have adequate time to prepare for today's matches."
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Streaming of New Zealand's first World Cup event was marred by issues including periods of reduced video quality such as pixelation and buffering.
After furious viewers took to social media midway through the first half to slam the quality of the coverage, Spark announced the second half of the game would be simulcast to free-to-air TV.
But fans without a Spark Sport account, SKY or Freeview were left without any way to watch the game, as it wasn't available on TVNZ's normal streaming service.
Spark said it's been working with its international streaming partners to "identify and resolve" the cause of the quality issues.
"We are very disappointed that some New Zealanders did not get the experience they deserved last night during such an important match and we apologise to those who were affected," CEO Jolie Hodson said.
"We are committed to giving New Zealanders a good viewing experience. Our immediate focus today is on getting things right for today's matches and for the rest of the tournament."
More than twice as many people tried to watch the All Blacks' match against South Africa than the Japan-Russia game the night before, which went off almost without a hitch.
Join us for live updates of the All Blacks v Canada match on October 2