Lee Byung-chun (2nd L), a professor at Seoul National University's school of veterinary medicine, poses with his assistants and the four cloned puppies at his laboratories in Seoul June 16, 2008.

A South Korean biotech company on Monday unveiled four Labrador retriever puppies it said were cloned from a Japanese dog skilled at sniffing out patients with cancer.

RNL Bio, affiliated with the stem cell lab of Seoul National University, said the puppies were born three weeks ago and would be sent to Japan in September for training.

The puppies are clones of a six-and-a-half-year-old black Labrador retriever named Marine, which is thought to have a well-honed sense for detecting cancer, RNL Bio said.

The cloning, requested by the Japanese stemcell company Seems, was conducted by a team led by Seoul National University professor Lee Byeong-Chun, it said.

"Marine has excellent characteristics for cancer sniffing and I hope the cloned dogs have the same characteristics," said Lee, who previously headed world's first dog cloning project.

Seems wanted to clone the dogs because Marine could not give birth to siblings following an operation to have her womb removed, it said.

"Thanks to the cloning technology, it (Marine) has been able to preserve its own genes," said a statement on RNL Bio's website.

Researchers in several countries are investigating whether dogs have the ability to detect lung, breast, prostate and skin cancer at an early and treatable stage.

They believe cancer cells create a scent not present in healthy cells, which can theoretically be picked up by dogs in breath or urine samples.