Police said they were called to Rocking Horse Rd on Tuesday afternoon after a car collided with two parked vehicles. No one was injured in the crash.
"It is reported the offender fled the scene with a firearm," a police spokesperson said.
Police are making enquiries to identify and locate the offender.
South New Brighton School was put in lockdown just after 2pm on Tuesday. The lockdown has now been lifted.
A school representative confirmed the school was put in lockdown and parents had been contacted.
A message from the school said police had advised the school of an incident in the area and to go into lockdown.
It said police let the school know when students could go home.
Police said cordons were in place and the public was asked to avoid the area.
