It is a last-ditch effort before a forced decision is made to remove the bins altogether.

City Mission operations manager Greg Howell said the organisation is spending thousands of dollars to upgrade security cameras at its bins, install sensor lights, and erect signage warning of prosecution.

He said he knew of instances where vandals set fire to donated goods, or defecated at the sites.

Up to eight vehicles were seen loading up at the Prospect charity bin last week.

``A lot of people will take goods, sort through it and then bring the rubbish back, but will act like they are donating and then take another load,'' Mr Howell said.

``You like to think the best of everyone but I just wish they would understand how much it hurts organisations like us.  We want to help people who are legitimately in need but this costs us a lot of money - removing two skips of rubbish every week.

``I feel sorry for the people who are legitimately giving us good, decent re-saleable goods and then someone else decides it becomes their right to take, steal, vandalise or ruin . . . one day it might be them in legitimate need and they will probably knock on our door.''

City Mission Newnham store manager Jeremy van Engen said the issue occurred because some members in the community continued to donate outside of store hours.

He said he was dealing with the issue by getting a passing taxi driver to phone him when he saw dumped items.

``People drive past, see it is good stuff and want it for themselves or to resell at a market,'' Mr van Engen said.

Mr Howell said it was a common problem  and he urged people to donate in store hours between 9am and 5pm.

Email ibird@examiner.com.au or Twitter @IsabelBird