Detective Senior Constable Wayne Ryan, of the Warrnambool police crime investigation unit, said it was a "despicable act" to steal from charities whose "sole purpose is to help the underprivileged in times of need".

He said the Salvation Army church in Warrnambool's Lava Street was broken into between 5pm Friday and 9am Sunday.

"Once inside an unknown person, or persons, has stolen a money box as well as a Les Paul guitar and an amplifier," the detective said.

He said investigators hoped to speak to a possible male witness aged in his 50s, who was seen driving a white Hyundai van near the scene at the time of the burglary.

"That van was seen nearby and the driver may be able to assist police with our investigation," Detective Senior Constable Ryan said.

He said it was not yet known how much money was stolen from the Salvation Army but that it was a "dog's act".

"To steal directly from people who are struggling is just disgusting," he said.

Detective Senior Constable Ryan said police were also investigating a burglary at Warrnambool's Pinky's Pizza between 5.30am and 6.50am Sunday.

"The offender gained entry by forcing an external wall attached to an outside toilet," he said.

"Once inside, the offender stole $565 cash and a Royal Children's Hospital fundraising tin which contained an unknown amount of cash."

The detective said the offender also stole unknown amounts of food and other property belonging to the business.

He said the offender fled the scene, taking a store trolley to move the stolen items.

"The offender is believed to have had a vehicle somewhere in the Cramond and Dickson car park at the rear of Pinky's Pizza," Detective Senior Constable Ryan said.

"Police are examining CCTV footage of the area in the hope of identifying the offender and the vehicle."

The owners of Pinky's Pizza took to Facebook on Monday to voice their disappointment.

"When times are so tough anyway, to steal money, destroy property, prevent us from opening and robbing our staff from shifts is an absolute dog's act," the post said.

"The lowest of lows included taking the Royal Children's Hospital donation tin - beyond disgusting."

The hospitality business was forced to open at 4.30pm on Monday, five hours after its usual opening time.

Anyone with information should contact Crime Stoppers or Warrnambool police.

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