The boys - David and Peter Woodforde - had been final seen using off on their bikes from their Christies Seashore house about 5.15pm on Tuesday 20 September.
Peter is 12 and David is 9.
Police mentioned they've issues for the boys' welfare, and are searching for public help to assist discover them.
"Each boys rode off on darkish colored BMX bikes," authorities mentioned in a press release.
"Peter is described as 150cm tall with a slim construct and black hair tied in a prime knot. He was carrying a blue/white zip up jacket, lengthy darkish pants and white NBL sneakers.
"David is 145cm tall, about 40kg with a slim construct, brief darkish curly hair with a blue tinge and brown eyes.
"He was carrying a navy blue faculty jumper, navy faculty pants and sneakers."
Anybody who sees the boys, or has data on their whereabouts, is requested to contact the police help line instantly on 131 444.