The arrests, by the National Crime Agency, are part of an operation linked to the seizure of 125 kilos of cocaine destined for Australia earlier this month.
The drugs, which would have had a UK street value of approximately £20million, were found in a specially constructed unit built into a diesel generator.
A 29-year-old man was arrested in Wickford, Essex, a 43-year-old was arrested in Much Hadham, Hertfordshire and a 42-year-old was arrested in Romford, Essex.
All are being held on suspicion of conspiracy to export a controlled drug and are being questioned by NCA officers.
Three men have been arrested in raids targeting an organised crime group
NCA
A sign outside the offices of the National Crime Agency (NCA) in London.
Yui Mok
Industrial premises in Rayleigh, Essex, South Ockendon and Feltham, west London, were also searched.
Officers found a generator with a hidden compartment at the South Ockendon address, cannabis plants and a number of stolen vehicles.
High value jewellery was also found at one address.
NCA Branch Commander Lydia Bloomfield said: “Our investigation has targeted a network we suspect was providing a rare and highly sophisticated service to other organised crime groups.
“A shipment of this quantity of cocaine from the UK to Australia is unusual, but demonstrates the global scale of the class A drugs trade – which causes violence and intimidation throughout its supply chain.
“This operation has been planned and carried out alongside our partners including Border Force and New South Wales Police.
"We work closely with partners around the world to combat the highest risk organised crime threats.”
