Veteran criminal Kok (60) and his 41-year-old son-in-law were both arrested in March in the Lebanon for allegedly arranging shipments of cocaine from South America.
They are suspected of smuggling 370 kilos of cocaine which arrived in Europe hidden among a shipment of bananas in Antwerp in 2020, and was later seized in a German supermarket.
But now, Dutch media are reporting that a huge stock of weapons - including rocket launchers - were also uncovered following his arrest.
The news site, Het Parool, claims the weapons discovery has not yet been made public because the Lebanon and the Netherlands are in talks about who prosecute the pair for the weapons.
They have reported the Netherlands hope to add the weapons case to the drug case if the two are extradited to the EU state.
Kok is a convicted drug trafficker and gun runner and is one of the most infamous gangland criminals in Dutch history.
During the 90s, he struck up a close working relationship with Christy Kinahan Snr when they were both based in Amsterdam.
It is believed the pair worked together to import millions of euro worth of cocaine and ecstasy into Ireland and the UK.
The Dutch gangster has close ties with two Lebanese brothers who areinvolved in international arms dealing and drug trafficking - and who were also associated with the Kinahan cartel.
In 2011, Kok's trafficking business was thrown into turmoil after he was jailed in the Lebanon after being caught with 53kgs of cocaine by police.
During his time behind bars, the Kinahan continued to do business with Kok's associates who were then based in Marbella.
In March, Kok and his 41-year-old son-in-law were both arrested at the request of the Dutch authorities, following an extensive investigation which analysed crypto communications.
Kok's relative is a suspected member of gangster Ridoun Taghi’s criminal network.
Taghi is himself a named member of a so-called international “super cartel” of which mobster Daniel Kinahan is alleged to be a part of.
The Dutch Public Prosecution Service has now issued an extradition request to Lebanon.
Taghi, who is facing accusations relating to six gangland murders in the Netherlands as well as drugs trafficking charges, is the alleged leader of the notorious Mocro Maffia.
Drug Enforcement Agency (DEA) documents sent to Dutch police identified Raffialie Imperiale, Taghi, Bosnian criminal Edin Gačanin, Richard 'El Rico' Riquelme Vega and Daniel Kinahan as the heads of the so-called ‘super drug cartel'.
According to the DEA, Imperiale, Taghi and Edin Gačanin also attended Kinahan’s wedding at the plush Burj Al Arab hotel in Dubai in 2017.