Russell McVeagh staff had sex with university students on a boardroom table at a post-seminar gathering, a senior law lecturer has alleged.
In response, the firm has said there was never a formal complaint laid at the time.
On Saturday night, Khylee Quince from Auckland University of Technology made the claims in a Facebook post.
She said while she was working for the University of Auckland some years ago, a student who attended a seminar held at Russell McVeagh came to her the next day and told her sexual behaviour had occurred.
The student claimed that after the seminar, both solicitors and students proceeded to get drunk at the firm's bar and Russell McVeagh staff had sex with university students on a boardroom table in front of the other students.
Ms Quince said she and a colleague complained to the firm's CEO, but were told the students involved were adults who consented to the sex. The University of Auckland allegedly had a similar response when approached, as the incident had not taken place on university premises.
"So it was no one's business and these 19-year-old young women were expected to have full agency in circumstances where predatory men (and potential future employers) could take advantage of them," she wrote in her post on Saturday.
Ms Quince said the alleged incident negatively affected the students involved "for years", while the person who told her about it was effectively shunned by their fellow students.
The allegations have come in the wake of other claims of sexually inappropriate behaviour by male lawyers at Russell McVeagh.
Two young female clerks complained after undisclosed incidents involving two older male lawyers in 2015 and 2016. One of the incidents resulted in a police complaint.
In response to Ms Quince's claims, a Russell McVeagh spokesperson said the firm has "zero tolerance of any sexual harassment".
"When allegations of any sort have been made we have taken action," she said in a written statement on Sunday.
"If proven, we have taken action appropriate to the severity of the misconduct. In some cases, this has resulted in termination of employment or a partner departing, regardless of their seniority."
She said the incident alleged by Ms Quince happened more than 10 years ago and because the sex was consensual, a formal complaint was never made.
An external review of the events of 2015 and 2016 will be carried out.