"The video ran for a long time, maybe two hours from 8am until the shop staff arrived at about 10am. Some people were shocked, but others just stopped and watched."
Another witness said the explicit display had been running from as early as 1am.
Tanya Lee, 29, was on her way to breakfast with her 7-year-old son, when she looked up and noticed the video.
"I took a second look because I just couldn't believe what I was seeing," Lee said.
"It's totally inappropriate and offensive, not something that you want kids exposed to and it's also embarrassing for Auckland as a tourist destination."
Lee said she expected no less than an apology and an investigation from Asics to make sure it doesn't happen again.
Staff at Asics Shortland St said the explicit display was running when they arrived, and that they turned off the screens.
"Unfortunately we are unable to make any further comments and our manager is not around," one of them said.
Asics head office has been approached for comments.