Acting Prime Minister Winston Peters says Spark's streaming of last night's World Cup match between the All Blacks and South Africa was an "abject disaster".
And he has vowed that the Government will get to the bottom of the issue.
"I can assure you we will find out as fast as possible as to what on earth is not going on," he told Newstalk ZB's Weekend Collective this afternoon.
His comments come after Spark announced it would simulcast today's Rugby World Cup games free to air on TVNZ after glitches with its streaming service during last night's key All Blacks game.
They also said customers unhappy with yesterday's service can request refunds.
Spark's video streaming service cut out for some fans during the match, with images of the game flickering, pixelating, blurring and buffering, or losing signal altogether.
Any customers who were unhappy with last night's service have been invited to request a refund, the telco said today.
However, unhappy customers would be required to fill in the refund form by no later than 11.59pm on September 29, it has been revealed.
"We will process your refund within 10 working days to the credit card associated with your Spark Sport account," Spark Sport said online.
Peters – who was forced to watch much of the game on his phone as the stream on his TV was interrupted – said Spark should have been better prepared for the event.
"They [Spark] were told to get ready and we hoped that they would be ready and they promised us that they would be and they're not.
"It's not satisfactory."
Asked if the Government was in contact with Spark over the issue, Peters said Spark was probably "beleaguered with all sorts of phone calls at the moment".
"I didn't want to wait around for a couple of hours like everyone else."
He said the Government was doing all it could to figure out what did, or did not, happen last night.
But earlier today, Broadcasting Minister Kris Faafoi said the Government would "leave it to Spark to answer the concerns around last night".
"We are happy there was the contingency with TVNZ's Duke channel and that it kicked in for viewers when Spark Sport identified issues.
"We will let Spark go through their technical process before we make any further comment but it is obvious that with an event like this, Kiwis expect better delivery than last night."
As this stage, he said Spark Sport had confirmed it was a problem from the US-based company which was providing the livestream into New Zealand and not any issue with Spark Sport's platform.
Peters also told Newstalk there should be, what he called, a "happy balance" where the state steps in and makes major sporting events free to air as is the case in other countries like the UK and Australia.
He said when it comes to the key games – such as the quarter, semi and the final stages – all those games would be free to air.
"For the first time, you're going to see them without cost, live in New Zealand."