RNL Bio, affiliated with the South Korean lab that produced the world's first cloned canine, said the puppies were born three weeks ago and would be sent to Japan in September for training.
The puppies are clones of a black Labrador retriever named Marine, which is thought to have a well-honed sense for detecting cancer, RNL Bio said.
"Marine has excellent characteristics for cancer sniffing and I hope the cloned dogs have the same characteristics," said Lee Byeong-chun, a Seoul National University professor who headed previous dog-cloning projects.
The university lab was once affiliated with disgraced scientist Hwang Woo-suk, who is facing trial for fraud in his human stem cell studies. Independent testing verified his laboratory produced the world's first cloned dog.
Scientists are studying whether dogs may be able to sniff the breath or skin of patients to detect cancer on the theory that cancer cells give off a special odour.