The Metropolitan Police in London said it had received 27 reports of abuse over the last year, up from 19 in 2012, including instances of children being dunked in a bath, being swung around by the feet and having their head banged.
Officers from Project Violet, the police's faith-related child abuse unit, hosted talks with community leaders and social care professionals to alert them to the warning signs of abuse carried out in the belief it will exorcise evil spirits.
"It's vastly under-reported," said Detective Superintendent Terry Sharpe, Project Violet leader.
Sharpe said that most cases came from African Christian and Muslim communities.
The issue came to light following a series of horrific cases.
Victoria Climbie, 8, was murdered in 2000 by her great aunt and her partner, who believed the girl was possessed while the torso of a Nigerian boy referred to as Adam was found in London's River Thames in 2001.
A couple were also sentenced to life in prison in 2012 after being found guilty of torturing and murdering 15-year-old Kristy Bamu, brother of the jailed woman.
"They (pastors) have so much power and influence in the community and there are rogue pastors who abuse it," she said.
Kanda admitted the difficulties faced by police in working with ethnic minorities, but stressed they were the main hope for many victims.
"Children accused of being witches are not likely to tell their teacher because for someone like myself it was normal, it was what I heard every day.
"When I was put in foster placement I was screaming, crying and I was scared.
Sharpe warned rogue pastors that the authorities were on their trail and could "covertly gather evidence".
"Our goal is to protect children," he said.
