She said: "Anecdotal evidence from our inspectors and from some police officers suggest that some of these individuals feel that the police will do something about it if they carry a knife or they carry a gun.
"But they're not so interested if they have got a dog that is aggressive or dangerous. And so it causes us great concern when we see the welfare of these dogs not being protected properly.
"And obviously, for the local communities, they're being put at risk by having dangerous dogs out there on the street."
The RSPCA is suggesting all owners get their dogs microchipped and that more dogs should be neutered.
Ms Robinson said it was owners who do not control their pets properly who should be targeted by the authorities.
Mobile phone footage of a fight aquired by the RSPCA
"We feel that very often the important agencies look at the wrong end of the lead and pin it on the dog, when in actual fact we need to change owner behaviour and actually tackle those irresponsible dog owners, so they don't give good dog owners a bad name."
The government says existing laws were reviewed last year and are tough enough to call irresponsible owners to account.
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