Elon Musk has voiced support for an anti-immigration demonstration in Japan, where numbers of foreign-born residents are low and a "Japanese First" party did well in recent elections.

The Tesla and SpaceX chief and former adviser to U.S. President Donald Trump has backed far-right parties in other countries, such as Alternative for Germany (AfD).

Commenting on Monday on a video of the modest rally in Japan posted on X by an account called The British Patriot, South African-born Musk said, "Good."

The account, which describes itself as a "Proud white British man with indigenous roots," said the clip showed Japanese protesters "demanding the deportation of all illegal immigrants."

"From Australia to Europe to Japan, citizens are uniting for remigration," it said.

The video appears to have been shot in Osaka on Aug. 30 and shows people holding Japanese flags and banners opposing mass immigration, including one that says, "Don't make Japan Africa."

Immigration levels in Japan remain low compared to other rich economies and surveys have put it far down the list of voters' concerns.

But with an aging population, one of the world's lowest birth rates and worker shortages in many industries, the number of immigrants is increasing.

In July, the anti-immigration Sanseito party did well in Upper House elections, growing its seat tally to 15 from two. In the lower chamber it has three lawmakers.

Its agenda echoes other populist movements around the world, railing against "elitism" and "globalism," and saying it will "bring power back to the people."