Fed-up residents fear problems with an overgrown patch of parkland are being kicked into the long grass.
Hollinsend Park has been trimmed neatly by Sheffield Council – apart from a single section where the grasses have grown more than four feet high.
Householders who live in properties backing onto the park say people have been going into the grass late at night and having fires, raising safety concerns.
Dad Malcolm Knight, aged 65, who has lived on Ridgehill Avenue for 38 years, said he had been told the grass had not been trimmed because of financial cutbacks.
He said: “The last time someone was in there it was quarter to two in the morning. I rang the police because I could hear noise and see their torches.
“At about half eight in the morning I saw them coming out again.
“The police said they had had a fire in there, which is really worrying.
“Once they are in the grass they are invisible and could be doing anything.
“There are elderly people living alone on this street and a couple of years ago we had problems with people leaving hypodermic needles and all sorts around.”
Mr Knight, a semi-retired sales manager, said he would be taking his concerns to the next meeting of the Friends of Hollinsend Park group.
A Sheffield Council spokesman said: “The area in question was removed from regular grass cutting two years ago, in order to allow the grass to grow longer between the stream and the boundary of properties on Ridgehill Avenue.
“The area was traditionally wet around the stream in early spring, making tractor grass cutting difficult.
“This area is inspected regularly by maintenance staff and litter picked. “
The spokesman added: “We are not aware of reports of anti-social behaviour in this area of the park but, if people have any concerns about this, they should call 101 or, in an emergency, 999.”