The canteen facilities used by the not-for-profit sporting body at Flinders have been broken into three times this year.

The most recent incident on May 18 went beyond petty vandalism, with a large amount of stock stolen.

As the damage bill from the incidents moves further into the thousands, Lake Illawarra Little Athletics president Howard McGarry said the club would have to consider options of how to make up the funds.

"Including the last break-in, it's probably cost us around $3500 this year, and for us that's a lot of money," he said.

"That's about what we have to pay the council each year to use the fields, and the canteen is really our biggest fund-raiser. We get a tiny bit of sponsorship but we rely on the canteen to make a lot of our money through the year.

"The first couple of break-ins they just made a mess and chucked food and stuff around, but the last time they stole a lot of stock, including a dozen boxes of Powerade and that's when it really starts to hurt us."

The last resort for the group would be increasing registration fees, something Mr McGarry said nobody wanted to do.

"If it keeps going this way then we're really going to have to look at raising the cost of registration. We really don't want to do that because it just makes it harder for families to have their kids involved.

"The only people who are being hurt by whoever's doing this are the kids who come to Little Athletics to have fun."

The break-ins were even more disappointing for Mr McGarry given the club's history in the area.

"We've been going for a long time, we were at King Memorial Oval, in Warilla, for 40 years and I think we had one break-in in that time.

"We came to Flinders because of the better facilities in 2010 and we've had three break-ins already."