Police wanted to charge him immediately but discovered that he had connections to the diplomatic community and were forced to release him without charge on HK$10,000 bail to carry out checks with the Chinese Foreign Ministry, via the Hong Kong government's protocol division, over his diplomatic status.

It was eventually established that the man did not have diplomatic immunity and he was charged by police on Friday. He has been released on bail again and is due to appear in Tsuen Wan Court tomorrow.

The sought comment from the Egyptian consulate last week. A man who identified himself as Consul General Mohamed Mostafa confirmed that they had "helped" the suspect, and initially agreed to a face-to-face interview. The consulate cancelled just hours before police laid formal charges against the 48-year-old.

According to senior law enforcement sources the diplomatic wrangling over the case left police unhappy that they could not charge the man immediately.

Under Hong Kong law diplomats in the city can invoke immunity from prosecution rights if the offence they are suspected of is not considered "grave", meaning that it carries a term of five or more years on conviction.

Latest police figures show the smuggling of stun guns through Chep Lap Kok is on the rise.

In 2011, passengers were found with stun guns in their luggage on 35 separate occasions - almost three cases a month - leading to the arrest of 37 people. So far this year, there have been 48 cases and 53 arrests.

Last week, in one of the biggest cases on record, another man, from Tunisia, was arrested after 50 stun guns were found in his checked-in luggage. The 27-year-old - who was trying to board a flight to Dubai when he was stopped - was jailed for three months after pleading guilty in Tsuen Wan Court to the possession of firearms without a licence.