The world's largest animal cloning factory is under construction in China, with plans to churn out dogs, horses and up to a million beef cattle a year, reports said, prompting online and scientific concerns Tuesday.

The 200-million-yuan ($31-million) facility will include cloning laboratories and a gene bank, the official Xinhua news agency reported.

It is being set up by Chinese biotechnology firm Boyalife and South Korea's Sooam Biotech -- whose founder was embroiled in controversy a decade ago over claims to have cloned human embryos -- along with two Chinese research institutions.

It will develop animals such as pet and police dogs, racehorses and cows, to be sold on the open market on an industrial scale.

The factory in the northern port of Tianjin is set to start production next year, with initial capacity of 100,000 cattle embryos a year, growing to one million, Xinhua cited Boyalife chairman Xu Xiaochun as saying.

"Chinese farmers are struggling to produce enough beef cattle to meet market demand," he said.

Boyalife reposted Xinhua's report on its website Tuesday.

But social media users expressed scepticism over consumer appetite for cloned meat, pointing out that the plant will be near the site of chemical explosions that killed at least 165 people in August, and that China is plagued with food safety scandals.

"Is this meat going to be sold in South Korea or China? If in China, please make our leaders eat it first," said one user.

Another commentator wrote sarcastically: "This beef definitely must first be saved just for the central government leaders; only after they and their families have eaten it for 10 years should they deign to give it to us, the people! Really can't wait!"

Zhu Yi, a professor of food science at China Agricultural University, told AFP that there would be "almost no difference" between cloned and real cattle, but that companies should not rush to put cloned meat on the table without "rigorous risk assessments and repeated experiments".

He added: "We cannot rush towards the cloned meat market."

- Dead dog -

China has been cloning animals since 2000, Xinhua said, four years after the birth in Scotland of Dolly, the world's first cloned sheep.

Their ranks include the "strong-willed pig", a porker hailed as a hero after surviving more than a month buried under rubble after the 2008 Sichuan earthquake, reportedly replicated six times over.

A joint venture between Sooam and Boyalife started China's commercial cloning market last year, Xinhua said, cloning three pure-blooded Tibetan mastiff puppies.

But many online commentators worried about the ethics of the new venture.

"Crazily evil!" wrote one commentator, with another asking: "Is the next step cloning people?"

Sooam is run by Hwang Woo-Suk, who claimed in 2004 to have derived stem-cell lines from cloned human embryos, a world first, and was lauded as a national hero in South Korea before it emerged that his research was fraudulent and riddled with ethical lapses.

Sooam's website lists instructions for potential customers who want to clone a dead pet dog: wrap the body with wet towels and store it in a refrigerator, rather than a freezer.

Chinese bioethical standards can vary from those of the West, and have prompted a number of high-profile debates, with prominent journals Science and Nature deciding not to publish Chinese research on the world's first editing of human embryo genomes.

The country's animal husbandry industry has boomed to meet the demands of its increasingly carnivorous and growing middle class, and is a major driver of demand for commercial cloning.

But the practice is controversial.

In September the European parliament backed a ban on cloning animals for food, and the halting of imports and products derived from them.