The Daily Telegraph reports Haskell's legal representatives have now sent a letter to Ms Newton demanding that she withdraw her allegations and confirm the incident on Sept 9 was no more than "light-hearted banter between herself and the players".
The deadline for the retraction expired on Saturday, and Haskell's legal representatives have warned they "will take the appropriate steps to clear his name and to recover his financial loss", the Telegraph reported.
The lawyer for the rugby player also said a video of the incident, recorded by teammate Dylan Hartley, will confirm Haskell's story.
Meanwhile Highlanders chief executive Roger Clark says he would not have signed Haskell if he thought it would damage the team's reputation.
Clark said he had been following the story's development and wondered whether it was a bit of a "media beat-up".
"If we thought it was a serious incident we wouldn't have [contracted him]," Clark responded when approached for comment.
"But you can't judge a person until you actually know what the situation is. My understanding is it is a storm in a teacup. But I only know what I read in the media and haven't had any feedback from James."
Clark said he did not have any plans to contact Haskell regarding the incident.
"We've got 30-odd guys in camp at the moment and are flat out worrying about that. It is not something we've thought about or talked about."
However, Clark accepted the incident could be perceived as damaging for the franchise.
"From our perspective, the Highlanders have taken some big steps forward with our brand and we're trying to connect with the people in our region.
"So if something like that happened on our watch we'd be pretty disappointed. But we back ourselves to make sure that sort of thing does not happen."
Ultimately, though, Clark does not believe it will reflect poorly on the franchise.
"I don't see it as damaging," he said. "James hasn't even played for us at this stage."
Haskell is playing rugby in Japan and is due to arrive in Dunedin towards the end of February.