Pyongyang action came as Bangladesh's Foreign Ministry on Monday summoned North Korean ambassador Ri Song Hyon and gave a 72-hour ultimatum to withdraw their commercial councillor Son Young Nam, who was briefly detained as he tried to sneak in gold on March 5.
"We summoned the North Korean envoy yesterday (Monday) and gave him the 72-hour ultimatum for the withdrawal of the diplomat," Foreign Ministry's Director General for East Asia and Pacific Wing Jashim Uddin told newsmen.
"We also warned him of tougher actions against any diplomat or official of the North Korean embassy if they were found involved in such crimes in future," a foreign office spokesman said.
Ri had apologised and assured Dhaka that appropriate action would be taken against the diplomat.
Officials familiar with the development said said Son Young secretly left Dhaka on Sunday night fearing harsher action.
Bangladeshi issued Son Young's expulsion order after releasing him under the Vienna Convention after the brief detention for interrogation.
Customs and police officials said Son Yung was tracked down as he arrived on a Singapore Airlines flight carrying the gold in his handbag.
The diplomat claimed that he had returned from an official tour to Singapore but could not produce relevant documents or proof. Bangladesh does not allow gold weighing more than two kilogrammes to be carried by passengers under the baggage rules.
However, the customs officials said in recent times they saw a rise in illegal gold movement as they seized nearly one tonne of the precious metal in the past 22 months, mostly from Middle Eastern countries, compared with just 15 kilogrammes captured over the previous five-year period.