The civil suit contends Ticketmaster, which has its headquarters in West Hollywood, Calif., conspired to divert tickets to popular events from its main Web site to www.TicketsNow.com, a ticket auction Web site it owns, Canwest News Service reported.
"Customers have voiced concerns over the fact that tickets for the most popular events can ostensibly sell out in minutes, only to become immediately available in the secondary market at much higher prices," Luciana Brasil of Branch McMaster, one of the two law firms handling the case, said in a news release.
The lawsuit was filed on behalf of all Ontario customers who bought tickets through Ticketmaster or TicketsNow.com since Feb. 9, 2007.
Connecticut Attorney General Richard Blumenthal is investigating Ticketmaster as well.
"I am deeply disturbed that Ticketmaster may be exploiting its market dominance -- funneling consumers to its subsidiary in order to inflate profits," Blumenthal said.
Blumenthal has criticized a planned merger between Ticketmaster and Live Nation, another major ticket selling operation.
"This possible $6-billion music mega merger -- combining two already-powerful companies -- creates a singular and dangerously dominant force in the industry that threatens to illegally cut competition and consumer interests," he said.