Australia's kangaroos are genetically similar to humans and may have first evolved in China, Australian researchers said today.

Scientists said they had for the first time mapped the genetic code of the Australian marsupials and found much of it was similar to the genome for humans, the government-backed Centre of Excellence for Kangaroo Genomics said.

"There are a few differences, we have a few more of this, a few less of that, but they are the same genes and a lot of them are in the same order," centre Director Jenny Graves told reporters in Melbourne.

"We thought they'd be completely scrambled, but they're not. There is great chunks of the human genome which is sitting right there in the kangaroo genome," Graves said, according to AAP.

Humans and kangaroos last shared an ancestor at least 150 million years ago, the researchers found, while mice and humans diverged from one another only 70 million years ago.

Kangaroos first evolved in China, but migrated across the Americas to Australia and Antarctica, they said.

"Kangaroos are hugely informative about what we were like 150 million years ago," Graves said.