The force said paedophile hunter activities can hinder investigations and lead to offenders walking free.
Det Ch Supt Tom Richards of Kent Police said it also diverts resources away from cases involving real children.
Kent group The Hunted One said: "Police should concern themselves more with tackling paedophiles than us."
But Mr Richards said: "There have been zero cases in Kent where a vigilante paedophile hunter group has identified an individual who has at that stage presented a real risk to a real child.
"In the last two financial years, vigilante groups in Kent have contributed to 20 individuals being arrested but my resources alone in the same period have arrested 299 people."
Professor Martin Gill, a criminologist working for Perpetuity Research, said: "There is nothing worse than a police investigation to get to its crescendo and then be undermined by an often well-intentioned but disastrous intervention."
The Hunted One claims to have caught 57 people, leading to 27 convictions.
In October last year, Mark McKenna from Northfleet was jailed for five years after he was snared by The Hunted One.
The 38 year-old thought he was meeting an 11-year-old girl for sex at Bluewater Shopping Centre in Kent.
But instead of talking to a vulnerable child online, he was speaking to the group of concerned parents.
Ben Bleach of The Hunted One said he could not understand why "a child has to be raped" before action is taken.

Lydia Wilkinson said she did not know at first whether her father Peter was going to survive the stabbing at their home in Stourbridge on 30 March.
She said looking after him was a "massive relief and an opportunity I didn't think I was going to have".
"I will miss them both so much," the 18-year-old added.
Aaron Barley, 23, of no fixed address, has been charged with their murders and with the attempted murder of Mr Wilkinson.
Lydia, who was at university at the time 50-year-old Tracey and 13-year-old Pierce were stabbed, spoke of her devastation.
Mrs Wilkinson was pronounced dead at the scene. Pierce died in hospital after paramedics battled to save him.
"For me especially it is a case of taking every day as it comes and counting your blessings and using the support around, definitely."
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She paid tribute to staff at Birmingham's Queen Elizabeth hospital who saved her father.
Lydia had been planning to collect Pierce from school the next day.
"I still can't believe that I will never see him again or pick him up from school on that Friday like I promised to do," she said.
"He was just so bubbly and full of life and he really did light up a room with his mannerisms and impressions."
Mr Wilkinson, who spent six days in intensive care, said he was "on the mend".
He suffered facial lacerations, "dozens of deep stab wounds and almost 100 stitches".
"It will take some time but obviously the emotional pain will take forever," he said.
Mr Wilkinson said: "I didn't find out until I woke up in intensive care that Pierce had not made it. It was devastating. Absolutely devastating."
He added his wife had been a "fantastic mum" and a compassionate, kind person."
"She was just beautiful, she was our angel," he said.
Vigilante groups seeking to expose paedophiles should stop taking the law into their own hands, Kent Police has said.
[NEXT_CONCEPT]
A student whose mother and teenage brother were stabbed to death is focusing on caring for her father who was also injured in the attack.