Winning the rights would be a huge boost for Sky, whose share price has fallen by more than 20 per cent following news that Spark has won rights to domestic cricket, including Black Caps matches in New Zealand.
Spark also has the rights to Rugby World Cup 2019.
A Spark spokesperson said they did not have any comment to make in response to Sky's likely new Sanzaar deal.
In early September, Sky was said to have put a $400m offer on the table to NZ Rugby and Sanzaar for the next five-year cycle, once its current rights deal ends in 2020.
The deal includes All Blacks tests, Super Rugby and Mitre 10 Cup matches.
The Sanzaar rights deal serves as a massive boost for the struggling Sky TV, whose shares this week plunged below $1 for the first time in its 21 years as a listed company.
Sky TV's share price dropped by 18c (16.22 per cent) to as low as 87c - a new record low - on the NZX this morning. The pay-TV operator had held the cricket rights since 1995.
Pay-TV broadcaster Sky has never specified what it paid for its current five-year contract with Sanzaar, which runs from 2016 through to the end of the 2020 season.
But an insider says it runs to $70m per year (close to Forsyth Barr's recent estimate of $65m), or $350m in total.
This week Sky competitor Spark secured broadcast rights to New Zealand Cricket.
The rights period is for six years and includes all international and selected domestic cricket matches played in New Zealand under the umbrella of NZC, Spark has revealed.
Media commentator Russell Brown said the division of Kiwi sports content between different broadcasters may mean Sky TV and Spark's prices have to drop.
"This makes it much more competitive. I think if there's multiple providers it's going to have to change everybody's pricing strategy, because there is a limit to how much people can spend. Some of that pricing is going to have to be broken up," Brown said.
"I think for viewers the concern probably isn't about Spark's platform. I think it's having the most serious test it'll ever have right now [Rugby World Cup 2019].
"But the concern for viewers is that it all gets very fractured and they end up paying for multiple services. And that might mean Sky itself changing its monolithic pricing model as well."
On September 30, Sky said it would seek shareholder approval to enter a deal worth more than $235m (that is, more than half Sky's market value) for the new Sanzaar deal until 2025.
The approval, will be sought at the pay-TV broadcaster's annual meeting on October 17.
Sky canned its dividend payments this year to help build a war chest to outbid increasingly competitive rivals for premium sports rights. The new management team - headed by Martin Stewart - see rugby as a linchpin in preserving its future, and this year bought online rugby platform RugbyPass for up to US$40m in cash and shares.
Morningstar Research analyst Brian Han said in a note that yesterday's loss of the domestic cricket rights highlighted Spark's aggression in pursuing premium sports broadcasting rights.
"As we have noted previously, maintaining compelling content is critical for Sky's transition, and ... makes the upcoming Sanzaar rugby rights imperative for Sky to retain," he said.
New Sky TV chief executive Martin Stewart has recently taken a number of steps to bolster his company's war chest amid negotiations with top sporting bodies - including cancelling the company's dividend, taking out a new $200m credit line and initiating a restructure that could impact 250 jobs.
