Speaking at a rally in Baton Rouge, Louisiana, Trump said he had spent time during the presidential campaign with workers who were laid off but forced to train foreign hires brought in to replace them.
"That's actually demeaning," Trump said. "We're not going to let that happen any more."
Without naming companies, he said firms would withhold severance pay from the workers unless they trained their foreign replacements.
"One of my first executive orders will be to ask the Department of Labor to investigate all visa abuses that undermine jobs and wages to the American worker," he said.