McMillan said it costs $700 a day to have a patient in a bed at Hospice.
The Monday before Easter, inwards good coordinator Peter Henry and other volunteers came to work to find a pile about 8 metres by 8m in size that they had to move from in front of the door so they could get the trucks out.
The pile contained beds, an old fridge, old couches, books and stationary, as well as household rubbish. That cost around $1000 to get rid of.
Then after Easter Weekend, staff found piles of banana boxes containing clothes and crockery, as well as mattresses. That was another $600.
McMillan said the shop has increased the number skip bin pick-ups a week from two to three. She said the bin gets emptied on a Friday, and what is dumped out the back of the store the weekend, would fill up most of Monday's bin.
Items left outside are unable to be sold because they have been exposed to the weather. Henry said Hospice doesn't have the facilities to clean and dry anything that gets wet.
McMillan said other people also rummaged through the items which had been dumped, essentially stealing the good things before Hospice could sort them out.
"People see stuff that's been gone through and it looks like rubbish so they leave their rubbish here."
The store accepts any second hand household items which are in a saleable condition.
"Please drop them off between 8am and 3.30pm Monday to Friday and 9am to 1pm on Saturday," McMillan said.
Habitat for Humanity general manager Carina Dickson said items are dumped at its Whangarei ReStore regularly - between once a week to once a fortnight.
On Sunday night, someone left an oven. Other items have included TVs, old linen, clothes, couches and whiteware.
She said the cost to get rid of the items varies but "it certainly adds up over the course of the year".
Dickson said the cost would be in the hundreds if not thousands.
"We want good quality, preloved items."
She said a good guide is to ask yourself whether you would give it to your neighbour.
Her message to dumpers is clear: "We then need to divert money we want to spend on warm dry homes for Northlanders, to dump your waste. Please think about that before you dump that at our door."
The SPCA second chance shop on Port Rd has the same problem. "Bits and pieces" are dumped weekly, and larger dumps happen roughly monthly.
Most of the items go into a skip bin, but that can mean an extra pick up, and therefore extra costs, which takes money away from the animals.
Salvation Army Kamo Family Store manager Gary Bottomley said it was not a significant issue at his store or the James St store.
He said the stores did not really have anywhere dumpers could leave anything, but some items do get dumped next to the donation bins outside the Salvation Army Church in Aubrey St.