"It's a pretty blatant obvious copyright breach," said Rick Shera, of Auckland firm Lowndes Jordan.
"The breach is in copying it from the TV screen and then as a separate breach in communicating it again. "
Mr Shera said the losses suffered by the copyright holder would be the basis of any damages claim and on the face of it, this could be 100,000 times $49.99 - nearly $5 million.
But it was unclear what level of proof was required to show an actual loss.
"Had it not been for the infringement, would 100,000 people have paid $50 to view it? The answer is probably no. The court would hear evidence on what the likely viewership would there have been and how would that have played out."
Another lawyer, Kevin Glover, said the end viewers of the unlawful live-stream might also have broken the law, but it would be unlikely for a copyright holder to sue them
Earlier, Lonergan came out swinging against the "complete lowlifes" who live-streamed the fight on social media, threatening to sue for thousands of dollars.
He said those who posted the live streams were "complete lowlife s***heads".
"If we can find who those people are we'll be looking to bill them, probably in the tens of thousands of dollars.
"There will be two choices when we find out who they are, we'll send them an invoice for tens of thousands of dollars and they can pay that or they'll find themselves in court. It's theft and they're lowlifes."
Lonergan said he wasn't aware of the Facebook streams when contacted by the Herald but those who did it can "expect a knock on the door".
"I'd also like to see if there's any liability for Facebook, because they've got to take action on this.
"Sky and ourselves are very hot on this and will police very hard ... Sky will know exactly who has been streaming it."
A man who live-streamed the Parker fight and wished to remain anonymous said he wasn't worried about Lonergan's comments.
"It's not the first time I've illegally streamed sport. If he's going to go after everyone who watched it, I know there were over 20,000 alone on one Facebook stream, so I'm not too worried."
He said the price of booking the fight, which cost $49.99 on Sky Arena, contributed to his decision to stream it for free instead.
"None of the people that I've talked to wanted to pay $50 for a one-off."
A Sky spokeswoman said they also plan to take action against those who live-streamed the fight.
"It's a form of theft, and we're always watching people who are trying to steal our content.
"It is something we can track."
She couldn't confirm that Sky was able to track the activity of users using Sky decoders.
A woman who wished to remain anonymous said while her husband went to a friend's house and watched the fight on Sky, she stayed home with her kids and streamed it on Periscope.
"There was a bunch of 600-plus people that I know of who watched it streamed on Periscope.
"This was just one stream that I was watching live from a household who booked it and was watching it in Sydney."
A popular live stream posted using live video on Facebook by 'A Day in the life of #BeastMoze' was viewed more than 100,000 times and had almost 1500 shares.
James Bryant streamed the fight over Facebook for others to watch, and said the cost of pay per view was ridiculous.
"I am one of those people who streamed the fight over Facebook using the new live video function to friends and family who did not have a Sky account or could not afford the pay per view fees - which are pretty ridiculous.
"I do not see a problem with it at all."
Mr Bryant believed it was unlikely Sky or Mr Lonergan would be able to hunt down all those who live-streamed the event.
"I challenge Mr. Lonergan to try to sue me - like anything that goes before court, evidence must be obtained.
"To be honest, it will be impossible to prove who has been streaming it."
Other fight fans have expressed their thoughts on live-streaming the fight to the Herald.
Vernon Taylor said he believed a lower price for booking the event would have discouraged people to seek alternative viewing options.
"Perhaps $29.99 would have resulted in less streaming, 50 bucks is where the theft is."
Kip Long said he watched the fight for free on TV in Papua New Guinea.
"Does that make me a lowlife for not paying for it?"
Keith Moran refused to watch the fight as he felt the price was too high.
"Maybe if media companies, sporting bodies, promoters and the like weren't so greedy in charging, quite frankly, exorbitant fees then people wouldn't mind pay per view but until then I'm afraid streaming will continue."
