A Vietnamese village has become "a supermarket for illegal wildlife trafficking" raking in millions of dollars, a special hearing was told Monday.

The two-day public hearing in The Hague is laying out the findings of a year-long undercover investigation by the new Wildlife Justice Commission.

The probe has provided "clear and irrefutable evidence of an industrial-scale crime hub in the village of Nhi Khe in Vietnam," said the commission's executive director Olivia Swaak-Goldman.

"Urgent, decisive action" was needed, she told about 200 people gathered at The Hague's imposing Peace Palace.

The commission, set up last year, has no power to bring charges, but hopes the hearing will push Vietnam and other countries to crack down on the global $20-billion (18.5-billion-euro) trade in wildlife poaching.

Five experts, including international judges, will set out recommendations on Tuesday for further action.

But it seems Hanoi has already been spurred into action ahead of a major international conference on wildlife trafficking it is hosting later this week.

On Saturday, Vietnamese authorities destroyed a stockpile of two tonnes of ivory and 70 kilos (154 pounds) of rhino horn, which had been uncovered by the commission.

Former US assistant New York attorney Marcus Asner, an advisor on wildlife trafficking to US President Barack Obama, said it was "a good step" but more was needed.

Nhi Khe had become "a supermarket for illegal wildlife" with "massive quantities of rhino horn for sale and huge quantities of elephant products" openly on display, he said.

The commission says it has identified 51 people involved in the illegal trade in Nhi Khe, operating out of 16 shops dotted around the small village. The names have been given to Hanoi.

But "justice has not been activated in this case by the authorities in Vietnam, despite months of discussions and clear and detailed evidence," said Swaak-Goldman.

During five return visits in 2015 and 2016, the undercover operation found $53.1 million worth of parts from rhinos, elephants and tigers in Nhi Khe, just 17 kilometres (10 miles) south of Hanoi.

There were parts from up to 907 elephants, 579 rhinos and 225 tigers. But there were also other dead animals for sale, including pangolin, bear, hawksbill turtles and helmeted hornbills.

They were smuggled to the Southeast Asian country mostly from Africa and overwhelmingly destined for customers in China.

- Massive profits -

After a sale is agreed, business is then conducted on WeChat, the Chinese version of the mobile phone messaging service WhatsApp, with the buyers providing account details of Chinese banks for payment.

"What is most lacking is enforcement, and this is based on the absence of political will," said international judge Motoo Noguchi.

"The culture of impunity prevails."

A series of undercover videos showed shopkeepers weighing piles of ivory and rhino horn. There were also hundreds of bangles, necklaces and figurines.

One elephant tusk was estimated at $29,000 -- a fortune in the country where the average monthly salary is $210.

One woman trafficked an estimated $2.2 million in products over 12 months from her mansion, with a brand new Mercedes outside, the commission's senior legal investigator Pauline Verheij told the hearing.

Despite crackdowns elsewhere, an interpreter told the team it was safer to shop in Nhi Khe as people there "had their connections" ensuring police turned a blind eye.