Clandestine Laboratory Squad detectives have seized chemicals destined to become up to five tonnes of methylamphetamines, dismantling a drug trafficking and manufacturing syndicate as part of an 18 month-long investigation.

Detectives, including members of the Horsham Crime Investigation Unit, executed a search warrant at an 81 hectare property on Tuesday.

More than 50 drums of precursor chemicals were located, weighing in at more than 10 tonnes, that were alleged to be used in the manufacture of methylamphetamines.

Also seized were two unsecured firearms, ammunition and a small amount of methylamphetamines.

Detectives interviewed a 59-year-old man arrested at the address, who was released pending further enquiries.

This seizure is the culmination of a 20-month-long investigation into an alleged drug trafficking syndicate operating within Victoria.

Since the investigation began in February last year, detectives have:

- shut down three large commercial clandestine laboratories in Coburg North, Pascoe Vale and Monegeetta

- recovered more than $1 million in stolen vehicles and motorbikes as part of a re-birthing operation

- seized eight firearms

- charged eight people

- seized commercial quantities of methylamphetamine, amphetamine and cannabis

It also includes the seizure of 6kg of MDMA, allegedly hidden in the sleeping bag of a man and woman about to board the Spirit of Tasmania at the port of Geelong on 21 August.

The 44-year-old Newport man was charged with trafficking a large commercial quantity of MDMA and remanded to appear at Melbourne Magistrates’ Court on 26 November.

The investigation remains ongoing.

Anyone with information about illicit drug activity is urged to contact Crime Stoppers on 1800 333 000 or make a confidential report at www.crimestoppersvic.com.au