Low-income fast-food workers in the US have taken part in nationwide protests to denounce President-elect Donald Trump's pick for labor secretary, a vocal opponent of minimum wage increases and "overregulation.”

The protest took place on Thursday in more than 20 cities outside CKE Restaurant’s Carl’s Jr. and Hardee's restaurants in a bid to stop Andrew Puzder from becoming US labor secretary.

Puzder, who leads CKE Restaurants, has complained for years that Obama administration policies have burdened the restaurant industry with higher costs and contributed to a "government-mandated restaurant recession.”

The protest was organized with the help of "Fight for $15" movement, an organization that has successfully lobbied for minimum wage hikes in several states and cities. The movement also seeks to unionize restaurant workers.

An enthusiastic supporter of Trump, Puzder has criticized efforts to raise the federal minimum wage to $15 and is widely expected to roll back policies such as those aimed at curbing unpaid overtime and improving worker safety.

"If Puzder is confirmed as labor secretary, it will mean the Trump years will be about low pay ... instead of making lives better for working Americans like me," said Terrance Dixon, 32, who makes $9 per hour working at a fast-food restaurant at a St. Louis, Missouri.

"I know first-hand that Puzder would be the wrong choice for America's workers," said Rogelio Hernandez, a worker at Carl's Jr. in Santa Monica, California.

A majority of US workers that are employed by fast-food restaurants are living in poverty or rely on government assistance programs such as food stamps to get by, according to a study released in 2013.

US fast-food restaurants pay their workers so little and offer limited work hours that it ends up costing US taxpayers billions of dollars a year, the study said.

Most of the jobs created in the US after the Great Recession has been low-wage or part-time jobs, according to the Bureau of Labor Statistics.