(CNN) Authorities in Malaysia are looking for 117 North Koreans who have overstayed their work permits, according to the country's Immigration Department.

Datuk Seri Mustafar Ali, director-general of Malaysia's Immigration Department, told CNN on Tuesday that authorities are seeking the North Korean workers.

North Koreans were temporarily barred from leaving Malaysia during a three-week diplomatic row with Pyongyang following the death of Kim Jong Nam , the estranged half brother of North Korean leader Kim Jong Un.

That standoff ended , but it revealed that a significant number of North Koreans lived and worked in Malaysia,

All of the 117 North Koreans wanted by immigration are in the state of Sarawak, Ali said.It is the only state that employs North Korean workers, the country's human resource minister said, according to state-run Bernama news agency.

Ali said the workers have been given one week to turn themselves in, and he said his department knows of their whereabouts.

"We will definitely go after them as their work permits have expired, and thus they are considered illegal workers," he said. "But first we would like to give them or their employers a week's notice to voluntarily turn them in."

Ali would not say which companies the men worked for but said they were in the coal and construction industries.

North Koreans have been employed in the Malaysian coal industry in the past.

In 2014, 46 North Koreans were employed at the Selantik coal mine in Sarawak when an explosion hit, killing three people -- including a North Korean -- according to Bernama.

The deputy minister of home affairs at the time, Datuk Seri Wan Junaidi Tuanku Jaafar, told reporters the North Koreans were brought in to work via a special arrangement between the Sarawak and North Korean governments because locals would not take the jobs and specialized workers were needed.

Domestic coal is believed to be the biggest source of North Korea's foreign currency. It accounted for a third of all of Pyongyang's exports in 2015.