Nine-year-old domestic shorthair Mo settled into her Ngunnawal home at the weekend with owner Pauline Battersby.

Mo had a 3cm brain tumour removed last month in a delicate operation which involved 10 specialists and seven interns and cost Ms Battersby $7000.

But her owner said Mo's surgery was worth every cent and defended her decision after the story ran in the media.

''There are a lot of people who wouldn't do it. But, again, I believe if you're going to have a pet, it's your responsibility,'' she said.

Ms Battersby, who works for the Australian Federal Police, said Mo and her other pets, cat Cleo and Maltese-Shihtzu dog Morris, were her family.

''As far as I was concerned, the euthanasia was not an option, my pets are like my kids and they're part of the family.''

Ms Battersby first noticed something wrong when Mo developed ataxia, a condition that left her wobbly and unable to walk properly.

''It was like she was drunk, she had no control over her legs, she would walk a couple of steps and fall over,'' she said. Mo was eventually referred to the University of Sydney, where a battery of tests and an MRI scan not a CAT scan revealed the tumour on her brain.

Veterinary surgeons Katja Voss and Ben Landon removed the tumour in a rare operation.

They had the help of anaesthetists, radiologists and other specialists.

Hospital vet Katherine Briscoe, who helped treat Mo, said the cat recovered quickly but the operation had had risks.

''You can have seizures [in the cat], you can have changes to their vision, so they become blind, you can have respiratory depression, or changes within the pressures in the brain.

''So it's a pretty full-on experience for them,'' Dr Briscoe said.

Mo is now back to her usual self and roams her home freely with little but a scar on her head.

Ms Battersby said she was prepared for some negative reaction after Mo's story was picked up in the media.

''I looked through some of the comments on the [internet] and about 99.9 per cent of them were really positive,'' she said.

''A couple of people said it's only a cat it might only be a cat to some people but not to me.''

But she did have one regret.

''I'm kicking myself now, I wish I'd have had pet medical insurance,'' she said.