We have the same issue in Harris Park. Neighbour in the block opposite feeds a dozen stray cats (many look sickly, some with broken tail) and several unoccupied old houses in this suburb (awaiting knock-down for more flat blocks to come) provide great breeding grounds for each next generation of the poor things.
Unfortunately he impact of cats is not limited to rats and includes native birds, possums, lizards etc.
Parramatta Council, like others, are too short-sighted to intervene. A Trap/Neuter/Release program would stop the cycle but they’ll only rent you a trap and have each one killed if you deliver it (bit too extreme for me). I checked a bunch of local organisations but none have got money for TNR anymore.
PS: I like cats, I’ve got a RSPCA rescued/neutered one but it will never see the outdoors. It’s irresponsible to let them roam and hopefully will be illegal nationwide soon (I think some local governments around the country have already done so?).
It’s just a sad situation.