A Sydney law firm has launched a class action on behalf of people who as children and adolescents were prescribed the anti-depressant drug Paroxetine.

Drayton Sher Lawyers has called for expressions of interest from people who were prescribed the drug, commonly known as Aropax in Australia, when they were 18 or younger.

Paroxetine was once the most commonly used anti-depressant in Australia.

Solicitor Tony Nikolic​ said hundreds of people had indicated they would join the class action, which he expects to file in the Federal Court at the end of May.

Paroxetine was a commonly-prescribed anti-depressant more than a decade ago and for a time was the most commonly used anti-depressant in Australia.