Being an Australian, we are expert at dealing with ants.

First of all put the cat's dinner dishes on a plate and pour a small amount of water around them. Top this up daily when needed.

Ants HATE water. Once the ants realise that they can't get at the food they will stop.

Secondly, find out where the ants are coming from and get some pyrethrum pump spray from the local hardware store. Pyrethrum is not toxic to cats but toxic to ants. Spray where they are coming in with a good layer of it. Do NOT mop or wet the area for at least 7 days and reapply when needed.