Toronto's new police chief wasted no time confronting the criticisms levelled at his profession as he was sworn in Wednesday, but promised "bold steps" under his term to better the force in Canada's most populous city.

Mark Saunders, the first black man to lead the force, was met with a standing ovation after outlining his vision during a packed swearing-in ceremony at police headquarters.

"The challenges are higher than ever before, the stakes are higher than ever before, but so are the opportunities to take bold steps," he said. "We have no excuses. We know what we have to do. I feel a great sense of optimism."

Saunders, 52, was selected as Toronto's top cop after an extensive international search to replace his predecessor, Bill Blair.

He has spent 32 years with the Toronto police and comes to his new job from the special operations command, where he managed 1,200 officers and 164 civilians in a department that included the homicide squad, sex-crimes unit, and guns and gangs task force.

As he took on his new post, Saunders acknowledged the challenges facing the force of about 5,500 uniformed officers and 2,500 civilians.

"Policing is at a crossroads. It is under scrutiny as never before. The legitimacy and sustainability of policing are under challenge from those who believe it is both seriously flawed and too expensive," he said.

"The challenges have never been greater, but so too, opportunities to examine everything we do, how we do, why we do, should we continue to do it, can we do it more effectively and efficiently."

Saunders takes over at a time of tension over "carding" -- a police practice of stopping people on the street for questioning. Visible minorities, especially black youth, have long complained they are disproportionately targeted for the stops.

While he didn't mention carding specifically, Saunders promised that under his command, Toronto police would work to improve their interactions with the public.

"Every member of this service has a personal responsibility to make sure their interactions with members of the community are marked by courtesy and respect," he said. "We have to ensure that our community engagements become smarter, surgical, that they are conformed and guided by the latest and most accurate intelligence. That they are guided by the law."

Saunders highlighted a new pilot project launched last week to test body-worn cameras, and noted that he was open to other technological innovations that would improve policing.

He also promised to examine all duties carried out by police officers to see if some of them could be done by properly-trained civilians.

Despite his expressions of optimism, at least some critics said Saunders needed to back up his words with actions, particularly on the issue of carding.

"He has to stop carding ... and I don't believe he will," said John Sewell, co-ordinator of the Toronto Police Accountability Coalition, who saw Saunders's three decades of service on the same force as somewhat of a weakness.

"One can assume he'll continue on with the culture and direction that he's learned with the Toronto Police Services, which I don't think is good enough."

Ellie Adekur-Carlson, chairwoman of the Network for the Elimination of Police Violence echoed that view.

"Nothing new is coming out of Mark Saunders," she said. "It's very easy to make those vague sweeping promises ... but when it comes to responding to tangible solutions that are being presented, you see how he's not really standing up to that."

As he began his term, however, Saunders was given a vote of confidence from his predecessor, Toronto's mayor, and the police services board.

Alok Mukherjee, the head of the police services board, said Saunders was the ideal choice to lead the force.

"We heard that Toronto wanted a chief who would listen to the ideas and needs of the community while partnering with the public in fulfilling its vision of a safe and functioning city," he said. "The board is more than satisfied that it found these qualities in Mark Saunders."