They were due back around May 14. Police now have concerns for their safety and have been searching for the pair for the past week.
O'Connor, who worked at Abel Tasman Kayaks, knew the area well and described herself as "passionate about nature and working in the outdoors" on the company's website.
"I'm proud of the fact that I'm doing what I love to do every day."
A Facebook post from the kayaking company said O'Connor was a "very competent outdoors instructor who we love to bits".
"We are hoping that this is just a miscommunication of an off the grid adventure," the post said.
Anyone who has been in the Anatori, Webb, Kokopu, Independent and Fraser river areas since May 8 and may have seen the pair should contact police on 105, quoting event number P042228949.