Sonny Bill Williams farewells the Eden Park crowd during the second Bledisloe test this year,

Sonny Bill Williams has tweeted a message of support of the ethnic Uighur group in China.

The former All Black posted on social media: "It's a sad time when we choose economic benefits over humanity", a message that follows reports that China has been rounding large numbers of Uighurs, a Muslim minority group, and detaining them.

It’s a sad time when we choose economic benefits over humanity#Uyghurs 😢❤️🤲🏽 pic.twitter.com/F5EIWIOY7n — Sonny Bill Williams (@SonnyBWilliams) December 22, 2019

Williams is not the first sports star to draw attention to the plight of the Uighurs – or the reluctance of some in west to be critical of China, which is regarded as a key market for sports such as football and basketball.

Earlier this month, Arsenal player Mesut Ozil posted on social media: "East Turkestan, the bleeding wound of the Ummah, resisting against the persecutors trying to separate them from their religion. They burn their Qurans.

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"They shut down their mosques. They ban their schools. They kill their holy men. The men are forced into camps and their families are forced to live with Chinese men. The women are forced to marry Chinese men. But Muslims are silent. They won't make a noise. They have abandoned them. Don't they know that giving consent for persecution is persecution itself?"

Ozil has suffered a huge backlash since his post, and the Premier League and Arsenal have been accused os distancing themselves from the former German international, effectively leaving him isolated.

PHOTOSPORT Sonny Bill Williams and Ofa Tuungafasi pray at the end of the Ireland match at the Rugby World Cup.

The New York Times reported in November that the Uighurs were being detained en masse in northwest China by Chinese authorities, forcing them into secretive "indoctrination camps".

The reports have sparked calls for sanctions against China from the European Union parliament.

In October, the Chinese government asked the NBA to fire Houston Rockets general manager Daryl Morey over a tweet that caused an international furore.

Morey's tweet supporting protesters in Hong Kong sparked outrage in and tension with China, and NBA commissioner Adam Silver said the NBA suffered "substantial" financial losses in that country.

Speaking in New York at an event organised by Time magazine, Silver emphasised what he described as his league's commitment to free speech, even at the potential cost of an ever-growing foothold in the lucrative Chinese market.

"We made clear that we were being asked to fire him, by the Chinese government, by the parties we dealt with, government and business," Silver said.

"We said there's no chance that's happening."