Other stores across the state are facing a similar problem, with people disposing of unwanted goods outside shops and collection bins instead of taking them to the tip.

Salvation Army waste and sustainability manager Donald Munro said an increase of dumping at all Victorian stores was causing major problems.

It meant staff were wasting time on removing rubbish, instead of serving customers.

Sunbury was among the worst-hit stores, Mr Munro said.

"We have two steel bins there, three cubic metres each [of rubbish which are] both emptied five days a week.

"That's around 3.3 tonnes a week - 170-plus tonnes a year - plus all the larger items we remove in our own trucks and take to landfill.

"We run our own donation trucks [two trucks, full time] to collect rubbish [from stores], which could be better used."

Mr Munro said that in Victoria, the Salvation Army last year spent more than $1.5 million on removing rubbish.

Most of the goods left outside the stores were not sellable.

"People dump stuff over the weekend when we aren't open. They clear out their sheds and garages and dump it at the door.

"It reduces the quality and because we're a soft target people think it's OK.

"We rescue what we can obviously, but increasingly we are not getting a great deal of usable goods left at our stores. Sometimes as little as 20-30 per cent is all we can salvage."

Mr Munro said customers were also being impacted.

"Every year we spend a lot of time and effort training our people to deliver excellent customer service in a retail environment and yet they end up spending hours each day cleaning up rubbish. It is not fair on them and it impacts on our customers."