The band's frontman, Jorge Herrera was accused of sexual abuse almost two decades ago in an anonymous blog post that went viral and caused an outcry on social media last November.
On their Facebook page Thursday, The Casualties continued to deny the allegations.
"The rumours about Jorge that allegedly took place almost 18 years ago are completely untrue," the post states.
"There is zero truth or fact to this story that is already old news. This fabricated story has been perpetuated from the start with no accountability or responsibility.
Rush to judgement
"Unfortunately, people have been quick to judge and have not taken the time to think that they are not only slandering a singer from a punk band, but also a father, husband and family man."
The post goes onto express sadness at the abuse the band has suffered on social media, and to say that they are looking into legal action to "once and for all put this 100 per cent untrue story to rest."
No criminal charges have been filed.
"This was a difficult decision, as the topics being discussed around these circumstances are very serious, yet currently remain allegations," promoters Blueprint Live and Venue Nightclub said in a joint statement.
"However, while we are committed to our fans and supporters in bringing in the best acts, it is always our main objective to provide safe and welcoming environments within our venues and to continue to uphold our strongly held values of safety and respect, across the board."
Ticket holders are being told that refunds will be available at the point of purchase.
The cancellation comes just days after news that Calgary's Palomino Club had pulled the plug on the band's scheduled Aug. 5 gig.