A pistol and bullets were found at a childcare centre in southwest Sydney on Thursday night.
The .45 calibre Webley Mk VI revolver and 58 rounds of ammunition were discovered in the garden during a police raid at the centre in Greenacre.
Police said no one was at the centre at the time. AAP reports the gun is undergoing ballistic tests.
"We believe that the offender or offenders involved in putting the gun there have put it so they have easy access when they want it," said Inspector Wayne Walpole.
"The kids in the childcare centre did not have direct access to it."