On October 10, the A-League club posted on Facebook an opportunity for members of the public to host their W-League team's American imports for the season.
It prompted several explicit responses, with advocacy group Women Sport Australia (WSA) angered over an apparent failure to immediately remove them.
"These sexually explicit and lewd comments are objectionable, inappropriate and derogatory to all women and especially to women in sport," WSA president Carol Fox said.
"They cast the Newcastle Jets club, the sport of soccer and Australian sport into disrepute.
"The fact that these comments were not moderated and not immediately deleted makes the club guilty of inaction and of failing to take a leadership role in their sport and in their community."
WSA have called on Football Federation Australia and the W-League to take action against those making the inappropriate comments.
The Jets have been contacted for comment.
The club also came under fire from some fans on Facebook for billeting the W-League players rather than finding them private accommodation.
"Want to be part of a great team? We're looking for host families for our American W-League players!" the Jets' post read.
"The girls will be in Newcastle from mid-October and staying through until mid-February, with the club covering expenses incurred as part of your hosting role."