Charity shops are urging people to only donate what they would accept in their own home following a surge in drop-offs of unsellable goods.
One Auckland store has to stop accepting donations for an afternoon while volunteers sort through large amounts of stock.
Emily Dearsly, of Mercy Hospice Shop in Ellerslie, said it was only taking two to three days for the store to fill a rubbish skip, where it would normally take about 10 days.
"It's normal for us to get a high number of donations at this time of year as people have a summer clean out," she said.
"We're eternally grateful for donations as we couldn't operate without them, but sometimes people need to be a bit more selective about what they're donating.
"Some people seem to see us as an easy way for them to get rid of things."
People often left items after hours directly below a sign which says, "please no donations outside of business hours".
"Some times we have to stop accepting donations for a few hours or an afternoon because we have so much to sort through," Ms Dearsly said.
Salvation Army Mt Wellington shop manager Gary Davison said increasing donations of unsellable goods were very costly for the store.
"We recycle as best we can but there's a lot of stuff that gets dropped off -- particularly after hours -- that we can't sell or recycle," he said.
"Couches with rips in them, or that a dog has had a good go at, often get dropped off at night.
"Even things that are of good quality, which are dropped off after hours, cause us a bit of a headache because they end up scattered around the neighbourhood and wrecked so it can be a big effort to clean up."
Volunteers didn't have hours to spend cleaning couches, or fixing broken items, he said.
"It becomes a health and safety issue if items are too decrepit. We can't give them to families.
"The same goes for any electronic goods which are faulty.
"We also can't sell any clothes which have holes in them or are dirty, or any household items which are broken."
The store also had the "two-prong" issue of having a lot of stock at this time of year but not enough volunteers to sort through it.
Meanwhile, the Red Cross charity shop in Mount Eden had so much stock it has had to temporarily stop accepting clothes, shoes and books.
"We're mega-full at the moment," a shop attendant said. "It's normal for us to be busy at this time of year but we picked up a lot more stock before Christmas than we normally do so we've got even more at the moment than we normally would in January."
People dumping "pure rubbish" was very costly for the store, he said.
The Red Cross store on Karangahape Rd was also busier than normal.
"We've got heaps at the moment but we're still accepting donations," manager Geanny Zamora said.
Charity shop tips
• Only donate what you would have in your own home.
• Donate during business hours. Some stores will pick up large items if arranged.
• Clothes need to be clean and not have any holes or rips.
• Houseware needs to be in good condition, not chipped, broken or faulty.
• If you'd like to volunteer, talk to a store manager.