WASHINGTON -- U.S. President Joe Biden took aim at online retailer Amazon.com Inc. at a labour event on Wednesday after touting his government task force on worker organization "to make sure the choice to join a union belongs to workers alone."

"And by the way, by the way, Amazon here we come. Watch. Watch," he said to loud applause at the North America's Building Trades Unions (NABTU) Legislative Conference.

Last week, workers at an Amazon warehouse in New York City voted to form the first union at the second-largest U.S. private employer, a victory that adds to recent grassroots successes by labour activists pushing into new industries.

Amazon did not immediately respond to a request for comment.

Biden is widely considered to be the most pro-union president in decades and has earned praise from the country's labour leaders.

He moved quickly to oust government officials deemed by unions to be hostile to labour and reversed rules of past U.S. president Donald Trump that critics said weakened worker protections.

The task force, which includes more than 20 heads of agencies and cabinet officials, including U.S. Treasury Secretary Janet Yellen and Defence Secretary Lloyd Austin, is an effort to help reverse decades of decline in union membership and power, labour experts said.

(Reporting by David Shepardson and Alexandra Alper in Washington; Editing by Matthew Lewis and Howard Goller)