It’s believed a woman attended the hall on Warrandyte Road, Langwarrin around 7.30pm while it was being used for competition basketball.
The woman accessed a room where officials keep their belongings and stole a handbag and two mobile phones.
It is believed the woman arrived and left the area in a grey Ford Territory.
Some of the stolen property was located in the carpark of a fast food restaurant on Lee Street, Frankston later that night.
Investigators have released images of the vehicle and a woman who they believe may be able to assist them with their inquiries.
Anyone with any information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential crime report at www.crimestoppersvic.com.au