Concealed glass has been discovered in a play area where a sharp blade was last week found embedded in a child's swing.
A blade was last week found in a child's swing
The find was made at a children's play area at Anderson's Park in Coleraine.
Police urged parents to be vigilant following a report that broken bottles were found concealed in wood chips.
SDLP MLA John Dallat said it was "sick that anyone would embed glass in wood chippings to harm a child". He claimed syringe needles have also been found.
"I think the razor blade was so horrific it's hard to speak of it, to think of some child perhaps just two or three years of age on a swing...
"It only takes one or two people to do it, but to focus their perverted attention on innocent children really makes me ill."
The PSNI praised the park warden who made the discovery on Monday and said that his actions "undoubtedly prevented a child from being injured".
Stephen Irons of the PSNI said: "The broken bottles were deliberately placed in such a way as to cause injury to children using equipment at the play park, and those responsible must have been aware of the consequences of their actions.
"This is a very worrying development, and we will not hesitate to deal firmly with anyone found endangering the safety of children in such a callous and cynical way."
Last Thursday, a sharp blade was found embedded in the seat of a swing.