"We have recently been made aware of allegations of misconduct against Andrew Kreisberg. We have suspended Mr Kreisberg and are conducting an internal investigation.
"We take all allegations of misconduct extremely seriously, and are committed to creating a safe working environment for our employees and everyone involved in our productions," Warner Bros TV Group said in a statement to Variety.
Kreisberg has been accused of engaging in a pattern of alleged sexual harassment and inappropriate physical contact over a period of years, according to 15 women and four men who have worked with him.
"There is nothing more important to us than the safety and well-being of our cast, crew, writers, producers and any staff. We do not tolerate harassment and are committed to doing everything we can to make an environment that's safe to work in and safe to speak up about if it isn't," said Greg Berlanti and Sarah Schechter, who head Berlanti Productions which oversee Kreisberg's shows.
More From This Section
Kreisberg has strongly denied the allegations.
He added that any inappropriate touching or massages never occurred.
Many women said they found the work environment created by Kreisberg to be so hostile and "toxic" that they leave a room when he enters it. Kreisberg reiterated his denial that he gave any staffers unwanted attention.
"I have proudly mentored both male and female colleagues for many years. But never in what I believe to be an unwanted way and certainly never in a sexual way," he said.