There's alarm someone may be intentionally trapping birds after five sparrows were killed by an adorned wire ring put around their necks.

In the last two weeks the SPCA has found seven birds wearing the neck-rings, which can trap the birds beaks and see them die a slow and painful death of starvation.

SPCA senior animal welfare inspector Ben Lakomy says this has gone on for some time now and the person doing it may not be aware how much harm they're causing.

"We're really keen to try and identify the people or the person responsible for this so that we can have a chat to them and try and get it stopped as soon as we can."