ST Vincent De Paul Ballina has installed a CCTV system and extra signage to reduce dumping and donation theft, which costs the volunteer-run charity about $3000 per month.
Pauline Shay, volunteer day coordinator, said elderly volunteers regularly waste time picking up unwanted items from the Martin St store's drop-off point.
"We're all volunteers and we try and run St Vincent's on as lean an amount as possible," she said.
"But when we've got to spend $3000 a month getting rid of unwanted rubbish, that's $3000 that doesn't go to the community.
"I think our volunteer staff come here with the right idea to help community. But when you've got to come clean up others rubbish it's often quite messy and we've got elderly women aged 70 and 80 picking up all this rubbish, sometimes in the rain."
Angelo Grande, St Vincent's recycling waste management facilitator for 27 stores from Tweed to Laurieton, believes increasing landfill costs contribute to the problem.
"We're very appreciative of donors. We could not do the work we do without that generous support, but in terms of receiving unsaleable donations, there's two types of donors," he said.
"The genuine donor who thinks we can take it and who is giving it to us for right reasons, but unfortunately we can't take those goods.
"Secondly, there is the dumper, who will dump on us anyway."
He explained the store can't take items such as furniture "because of its bulky nature, the smaller size of some of our retail spaces and also the elderly nature of our volunteers".
But, Mr Grande said other charities and government recycling facilities in the area take furniture and goods St Vincent's is unable to accept.
"If a donor is unsure please ring the store (on 02 6686 4072) and check. We can direct them to another store," he said.