“This is slave labor,” said Agnes Jongerius, a Dutch member of the European Parliament, who has urged European authorities to force Poland to stop admitting North Korean workers.

Ms. Kowalska scoffed at allegations of abuse and said the North Koreans she managed enjoyed “a normal life.”

“They asked us for advice on what to buy their wives and kids,” she said. “They liked to buy lingerie for their wives. It was a popular gift, and they would ask us about inexpensive shops.”

She said her company paid the workers about $780 per month. She acknowledged at first that Armex sent a portion of their wages to a North Korean company, but later said she had misspoken and no one took a cut.

As international scrutiny has intensified, the State Labor Inspectorate has vowed to investigate claims of abuse. So far, the agency has found “no signs of forced labor,” said Dorota Gorajska, an official responsible for companies that employ foreign workers.

Officials acknowledged, however, that inspections have generally been confined to paperwork and that when interviews are conducted, investigators typically rely on translators provided by employers.

Given North Korea’s reputation, does that not taint their findings? An official at the inspectorate, Michal Tyczynski, took a deep breath.

“It’s a tricky question,” he said. “There is no good answer to this question.”