US President Joe Biden slammed Kellogg's management for replacing striking workers and urged the breakfast cereal giant to negotiate a solution to their labor dispute.

Biden, a longtime champion of unions, said he was "deeply troubled by reports of Kellogg's plans to permanently replace striking workers" and vowed to "aggressively defend" collective bargaining.

"Collective bargaining is an essential tool to protect the rights of workers that should be free from threats and intimidation from employers," Biden said in a statement.

The company on Tuesday announced it would replace workers after members of the Bakery, Confectionery, Tobacco Workers and Grain Millers International Union (BCTGM) rejected the latest contract offer.

"Permanently replacing striking workers is an existential attack on the union and its members' jobs and livelihoods," Biden said.

Kellogg's plant workers remain on strike after rejecting the company's latest contract offer
Kellogg's plant workers remain on strike after rejecting the company's latest contract offer GETTY via AFP / Rey Del Rio

"I have long opposed permanent striker replacements and I strongly support legislation that would ban that practice."

The company responded saying it had "made every effort" to secure a wage deal with labor.

"We agree that this needs to be solved at the bargaining table. Our objective has been -- and continues to be -- to reach a fair agreement for our people," Kellogg spokesperson Kris Bahner told AFP.

However, Bahner added, "We have an obligation to our customers and consumers to continue to provide the cereals that they know and love -- as well as to the thousands of people we employ."

The union said the strike against Kellogg's, which began October 5 in Battle Creek, Michigan; Lancaster, Pennsylvania; Omaha, Nebraska and Memphis, Tennessee, continues.

Among other grievances, the workers reject the company's two-tiered wage structure.