Five steak knives have been found buried in the sand at the new Kershaw Gardens playground in Rockhampton.
The Rockhampton Regional Council is in the process of reviewing CCTV of the area after the discovery.
The council said the knives were lying flat in the sandpit and there were no reports of injuries.
Mayor Margaret Strelow said the knives were found this morning, three by members of the public and the other two by council staff.
She said a thorough search of the area had taken place and no other knives had been found.
“This behaviour is sickening and malicious, and not normal for our community,” she said.
“I hope those responsible think carefully about what they’ve done and consider if they would really be prepared to face up to what could have been very serious consequences.”
The new playground has been extremely popular with families since it opened three weeks ago, attracting hundreds of visitors a day.
It is part of a $16 million redevelopment of an area damaged by Cyclone Marcia in 2016.
It was officially reopened by Premier Annastacia Palaszczuk at a public event.
Cr Strelow said council workers inspected the equipment and double-raked the sand every morning.
“We take the safety of those using our facilities incredibly seriously,” she said.
“We are aware of similar incidents taking place elsewhere, with people intentionally trying to make play equipment, sand, and synthetic soft-fall surfaces dangerous.”