The mayor, also an East Riding councillor for St Marys ward, said gatherings began when local teenagers held vigils for a 15-year-old boy killed after a collision with a car on Molescroft’s Woodhall Way in April.
But she claims what started as peaceful gatherings have since been supplanted with rowdy youths who appeared older bringing in booze “by the crate load”.
A Humberside Police spokesperson said officers now patrolled the area every evening following reports of littering and antisocial behaviour from nearby residents.
Coun Johnson said broken glass and discarded cans left in the wake of the meet ups had already seen a six-year-old by cut his foot.
She added she feared someone could “end up in hospital” if litter continues and that a dispersal order could be requested to stop them.
The mayor said: “The kid who was killed was popular with his classmates so at first they were holding vigils on Woodhall Way.
“They were just gathering there, holding candles, pictures and flowers, but they had to be moved because they were blocking the pavement.
“There now seems to be youths coming from Swinemoor and as far away as Tickton, they’re not 15-year-old kids anymore.
“We’ve had complaints from residents who say they’re staying until the early hours, some have said they’re bringing drinks by the crate load.
“The trouble is the noise and the mess they’re leaving, the litter is a huge problem.
“The park is popular with dog walkers from as early as 7.30am, they’re coming on there before the caretaker has chance to clean up.
“Litter pickers with the Wombles of Beverley have volunteered to clean up, but they’ve had to start going down in shifts because of amount.
“We think some of the bottles have been thrown and smashed deliberately, it’s shameful, antisocial and illegal.
“Molescroft Pavilion is such a fantastic facility but its being spoiled for the many by the actions of a few.”
Parish councillor Fleming said the gatherings had left several nearby residents “very tired and worried”.
The vice chair said: “The youths flood onto the field after the care taker’s locked up, it’s causing sustained noise most evenings but the weekends are the worst.
“Everything’s up for discussion with the police, it’s in their hands now.”
Humberside Police’s neighbourhood Sergeant Lucy Kevan said: “We are patrolling the area every evening and are engaging with those who regularly visit.
“We do have a group of young people who use it as a meeting spot following the recent lifting of some of the coronavirus restrictions including 30 people being able to meet outdoors.
“Whilst this area is often used as a place to socialise, we are reminding people to be considerate of nearby residents and to respect the law.
“We have also recently conducted HumberTalking surveys in the area, which enables us to use that information, reports and intelligence to assist our teams.
“Our conversations are ongoing, as is our proactive work in this area. A member of our Neighbourhood Policing Team will be attending the next meeting to gather relevant information.
“If you wish to report any incident or concerns, please come and have a chat with us when you see us out and about.”
The police said all such incidents could be reported on the 101 line or by calling Crimestoppers on 0800 555 111.