At issue is whether the officers can have a lawyer vet their notes before submitting them to the watchdog.
Ontario's Court of Appeal has ruled the officers should not do that.
The case arose after the families of two men shot dead by police argued officers were playing fast and loose with rules mandating their co-operation with the Special Investigations Unit.
In pressing an appeal, the officers argue the Ontario court was wrong to all but eliminate their right to counsel, saying it is simply unfair to them.
In agreeing to hear the case today, the Supreme Court of Canada dismissed an attempt by police groups to intervene at this stage.
The court also granted the director of the SIU, Ian Scott, more time to prepare his leave to cross-appeal.
Scott believes the Ontario Appeal Court didn't go far enough in stopping officers from consulting lawyers before they deal with his agency.
In separate incidents in June 2009, Ontario Provincial Police officers shot and killed Doug Minty, 59, and Levi Schaeffer, 30.
In clearing the officers of any wrongdoing, Scott issued a scathing statement in which he said he could not determine what had happened because the police notes were unreliable.
Toronto lawyer Julian Falconer, who acts for the families, said it was not surprising the Supreme Court had recognized the national importance of the integrity attaching to police officers' notes.
"(But) this is a tough burden for two families who were simply seeking justice in how their sons' deaths were investigated," Falconer said.