The body was found wrapped in black plastic while its placenta was placed in another plastic, inside the box.
District Police Chief, ACP Awang Besar Dullah said the garbage collector alerted the police at about 11.40am.
"He was collecting recyclable materials when he found a box and when he opened, he was shocked to see the dead baby.
"We believe the infant was newly born and no injury was found on his body," he said, adding that the last trip for lorries to dispose wastage to the landfill was at 4am.
Awang Besar said the body has been sent to the Tawau Hospital for a post-mortem. So far, he said no suspect has been detained.
In light of this, he called on public who may have information to come forward to facilitate police investigation.