United States technology billionaire Elon Musk faces a backlash in Germany after endorsing the country's main far-right political party in a newspaper opinion piece that led to an editor's resignation and accusations of foreign interference.

Musk's guest column in a leading conservative newspaper, Welt am Sonntag, described the anti-establishment Alternative for Germany, or AfD, party as Germany's "last spark of hope", expanding on his earlier endorsement of the party posted on X last week.

The controversial article, published online on Saturday, prompted the newspaper's commentary editor to resign in protest and drew condemnation from most of the country's mainstream political parties, reported Reuters.

The endorsement comes at a sensitive time for German politics, as voters prepare for an early election on Feb 23 following the collapse of Chancellor Olaf Scholz's three-party coalition government amid disputes over economic policy.

Musk's intervention is also notable given his role as an adviser to US President-elect Donald Trump's administration.

In his translated commentary, Musk said the far-right party "can lead the country into a future where economic prosperity, cultural integrity and technological innovation are not just wishes, but reality".

He added: "The portrayal of the AfD as rightwing extremist is clearly false, considering that Alice Weidel, the party's leader, has a same-sex partner from Sri Lanka! Does that sound like Hitler to you? Please!"

Musk claimed Germany faces "the brink of economic and cultural collapse" and said the AfD "can save Germany from becoming a shadow of its former self".

"The traditional parties have failed in Germany," Musk wrote. "The AfD, even though it is described as far-right, represents a political realism that resonates with many Germans who feel their concerns are ignored by the establishment."

Musk defended his right to comment on German affairs, citing his business investments in the country with Tesla Motors.

In his post on X last week, Musk wrote "only the AfD can save Germany" while endorsing the party's stance on regulation, taxes, and market deregulation.

Eva Marie Kogel, Welt am Sonntag's opinion section editor, announced her resignation on X shortly after Musk's article appeared online.

Despite polling second nationally, the AfD faces unified opposition from Germany's mainstream parties, which consider it too extreme for coalition government.

The leader of the center-right Christian Democratic Union, or CDU, Friedrich Merz, who is expected to become the next chancellor, condemned Musk's intervention, comparing it to a hypothetical German businessman endorsing a US presidential candidate. Merz labeled the piece "intrusive and pretentious".

"Let's just imagine for a brief moment what the Americans' justified response would be to a similarly one-sided article from a prominent German businessman in the New York Times that favored an outsider in the American presidential election," Merz told the Funke media group, a consortium of newspapers and magazines.