There is a large urn outside Mr Wai-Poi's front door with several dozen socks - about six months' worth.
Soon they will be washed and taken to the charity bins, before another swathe turns up.
"We inherited him about eight years ago, when he was 3. He's a pretty timid cat, it took him a while to settle. Then he started bringing these socks home. He just kept doing it and I don't think he's going to stop.
"They are mainly kids' socks, not so many adults'. I guess if you have a low line or a clothes horse, yeah, he'll take them."
The Mandalay cat sleeps most of the day to give him energy for his evening escapades, Mr Wai-Poi said. Although daylight capers aren't unheard of, he added.
Oscar has been spotted at nearby Bayfield Primary School, stealing the socks out of children's shoes while they play.
Mr Wai-Poi used to visit nearby homes with a basket trying to return the stolen socks, but has given that up. Most of the neighbourhood is aware of Oscar's antics, he said.
"I don't know why (he does it)."
The reason, says feline and canine behaviour specialist Lynne O'Malley, is often a lack of mental stimulation at home. Purebred cats such as Mandalays are particularly prone to thievery. "It's generally the more intelligent cats," Mrs O'Malley said.
"Those Oriental-type breeds are bred to be companion cats. They are quite intelligent and with that they can be a bit eccentric. They tend to need greater stimulation."
Pam Johnson-Bennett, a Canadian cat expert who has written books such as Think Like a Cat and is the star of a soon to be aired Discovery Channel television series Psycho Kitty, cats steal for fun, for attention or stress relief. In an article on her website titled Is your cat a thief? Johnson-Bennett writes cats sometimes suck wool as a self-soothing mechanism so "the objects stolen may include socks or other cloth items".
