In a separate statement, Sky TV said it and Vodafone were assessing the report "so that they can determine their future steps in relation to the proposed merger, if any". The companies filed High Court papers to make sure any appeal would fall within the statutory timeframe.
The companies want to create the country's largest telecommunications and media group, with Sky TV buying Vodafone NZ for $3.44b, funded by a payment of $1.25b in cash and the issue of new Sky TV shares at a price of $5.40 per share. Vodafone would have become a 51 per cent majority shareholder in Sky TV, in what amounted to a reverse takeover. The pay-TV operator planned to borrow $1.8b from Vodafone to fund the purchase, repay existing debt and use for working capital.
The regulator said the merger could boost competition in the short-term as companies fought more aggressively for customers. However, that would change over time and the commission said it couldn't rule out at least one of the significant TSPs "would suffer a significant loss of scale", squeezing margins and reducing their ability and incentive to invest.
"This, in turn, would allow the merged entity to raise or maintain prices at levels higher than would prevail absent the merger," it said.
The regulator said it didn't need to reach a firm conclusion about which sports rights are premium, and that it was sufficient to recognise Sky holds the rights "to the majority of popular live sports content in New Zealand, for which there is no close substitute."
As more premium sports is watched online, the regulator said it anticipated consumers would value bundled packages of telecommunications and content more highly, and those "offered by a single supplier such as the merged entity are likely to be even more attractive to consumers who view their content and broadband and/or mobile services as closely related, if not as one and the same thing."
The regulator said New Zealand differed from other nations in that only one broadcaster holds the majority of live sports rights, and that there aren't any anti-siphoning laws to prevent pay-TV operators buying monopoly rights.
"This potentially makes the rights to these sports more valuable than elsewhere, and switching to the merged entity may be higher than might be expected elsewhere, given there would be only one provider of integrated broadband bundles containing premium live sports content," it said.
Sky shares fell 0.8 per cent to $3.82.