In the past month two Ballarat Football League clubs and the city's only Victorian Football League club have had valuable items stolen while players have been training and playing.

Yesterday, BFL chief executive officer Rod Ward warned clubs to be diligent around their buildings. He asked them to lock change rooms and offices when not in use and during games or training.

He described thieves targeting community-based organisations as "lowlifes'' who had identified football clubs as a valuable source of income.

Four lap tops and a hard drive were stolen from the North Ballarat Football Club offices in three separate incidents while team members trained and played.

North Ballarat chief executive officer Mark Patterson said the club had installed new security following the thefts.

"We have reviewed our security measures around the place,'' Mr Patterson said.

Other thefts occurred at Sebastopol Football Club, where players' bags were stolen and ransacked, and East Point Football Club, where players' cars were broken into and wallets stolen while training.

Mr Ward said club members had responded to the increased security measures positively.

"They are all very determined to be on the look-out,'' he said.

Mr Ward said it was not unusual to have one or two thefts a year, but a spate of thefts was a problem.