"I want to extend my personal apologies to the young woman at the centre of this issue," Denis said Friday at a news conference in Calgary.
"This is an issue that should not have happened and we will take steps to ensure it does not happen again."
Denis made the comments following the release of a departmental investigation into the case of Danielle Polsom, 27, of Airdrie, a bedroom community north of Calgary.
Polsom went to police in the fall of 2009 to complain about sex assaults that had occurred for years, dating back to when she was nine. Last fall, the Crown stayed the charges against her alleged attacker because procedural delays had dragged on for so long that the accused's right to a timely trial had been violated.
Polsom has agreed to be identified and a judge recently agreed to lift a publication ban on her name.
Polsom held a news conference Friday afternoon where she said she was pleased at the outcome.
"Hopefully ... they're going to follow through and their apology was honest and everything they had to say isn't just to make one person feel better, it's actually going to make a difference," she said.
Her mother, Alison Jones, said her daughter felt devastated and betrayed when the case was dropped. Polsom started a petition demanding changes to the system.
"We think it (the report) is awesome. It's a great start. There's still some stuff that's on our petition that we would like to see done, but a lot of it is great," Jones said in a telephone interview with The Canadian Press. "We want to see changes so it doesn't happen to somebody else.
"There's nothing that's going to make our case any better, so let's try to make it better for somebody else."
Greg Lepp, assistant deputy minister in charge of prosecutions, said a number of factors led to the breakdown in the Polsom case.
The chief mistake, he said, was that police and prosecutors laid charges before the investigation was complete. That forced them to continue their probe while the case was before the courts. Running an investigation alongside a court hearing produced multiple delays and extensions.
Compounding the problem, he said, was that a prosecutor was not assigned to the file for four months after charges were laid.
"There were a large number of adjournments in this case, and in some cases in Alberta there are a large number of adjournments," said Lepp.
"There were way too many in this case."
Lepp and Denis said the government is moving to streamline prosecutions on a number of fronts, including ways to expedite traffic ticket hearings, which take up an inordinate amount of time and draw staff from other cases.
Other planned changes include setting up case management offices to handle some routine matters that used to be handled by a judge, an online system for lawyers to book court times and a renewed emphasis on assigning one prosecutor to a file to ensure continuity and ownership.
If necessary, the Crown will be asked to move a trial to a courthouse in a different region if the alternative is to have the trial not heard at all.
Lepp said prosecutors will also, in extreme circumstances, be allowed to bump minor cases such as shoplifting and mischief down the calendar. That could result in those cases being tossed out for lack of a timely hearing, but better those than the serious ones, he said.
A court culture that is accepting of routine and lengthy delays must also be addressed, he said.
"The prosecution service has enough control over the system that I can commit to you today that no serious violent case commenced after today's date will be lost due to delay."
Polsom's case went public last November when she told her story to Opposition Wildrose critic Rob Anderson, who represents her riding in the legislature. He raised the issue during question period, which prompted Premier Alison Redford and Denis to order an investigation.
On Friday, Anderson praised Polsom for her willingness to come forward.
"If this saves even one victim, the pain that Dani's had to go through and this family had to go through, then this whole ordeal would have been worth it," he said.
"It's a great first step."
The changes are expected to be implemented over the next three to five years.
Denis said he will be getting a followup report in three months.