After a joint investigation involving Northern Territory officers and the Australian Federal Police, six men have been charged with serious drug and other offences.

Police allege a 49-year-old NT drug dealer had organised for couriers to take money to Bali on his behalf to invest in clubs and bars in an attempt to launder it, as well as investing in businesses, property and vehicles in Australia for the same purpose.

The money was allegedly the proceeds of cannabis dealing, with police also claiming the man supplied drugs to more than 100 people from his Darwin apartment.

Investigators claim the man sourced commercial quantities of cannabis from several people, including two men who were arrested during attempts to deliver drugs from South Australia and Victoria.

A 54-year-old man, from Howard Springs, was the first charged in February after investigators intercepted a delivery of 23.6 kilograms of cannabis being sent by freight from South Australia.

A second man from Darwin, was arrested earlier this month as the 36-year-old allegedly tried to transport 32 kilograms of cannabis from Victoria hidden in compartments in his utility.

The 49-year-old was arrested and charged on Wednesday along with three other men, aged 32, 35 and 42, after searches were conducted on various properties.

Police said more than 60 kilograms of cannabis, with an estimated street value of up to $1.5 million, a number of vehicles and almost $50,000 in cash were seized during the operation along with sapphires, opals and other precious stones.

The AFP said investigations into the drug supply network are ongoing and further charges might be laid.

Superintendent Matthew Ballard said the arrests were another example of the commitment to causing maximum damage to the criminal environment in the Northern Territory.

Most of the men charged will next appear in court in May.

Australian Associated Press