Footage circulating on right-wing websites shows Wiles and another woman sitting on the beach having a chat, without masks.
At one point the other woman goes for a brief swim as Wiles watches.
The top microbiologist, who's been advising Kiwis on the pandemic response and has been a strong advocate for always wearing your mask outside, has been accused of breaching lockdown rules.
In an interview with Newstalk ZB this afternoon, Wiles explained that, while her friend did break the rules by going for a swim, she did not break any rules herself, as her friend is part of her bubble and she cycled the 5km from her house to the beach.
Wiles said she made a judgement call that she didn't need a mask and was monitoring how many people were around her.
She told Heather du Plessis-Allan that the experience was a lesson that you had to be careful what you did in public because someone was always watching.
Asked about the controversy during a Zoom call, the opposition leader ripped into Wiles.
"I think she's a big, fat hypocrite, actually," Collins said.
"I'm sick and tired of listening to her telling everyone else what to do."
Collins also insinuated Wiles had broken the rules by visiting that beach, 5km from her home, saying "unless she ran there, and I doubt it, then she wasn't exercising".
Wiles has clarified that she did indeed ride her bike to the beach, which is a form of exercise.
"I'm sick of her telling us what to do and she's not doing it... just do it," Collins added during the Zoom call.
Asked about Collins' description of Wiles as 'a big, fat hypocrite', a spokesman told the Herald the comment was a "well-known colloquialism" and had nothing to do with Wiles' appearance.