Authorities claim to have seized the equivalent of 500,000 hits of the "party drug" GBL, known on the streets as liquid ecstasy or "coma in a bottle", in the second largest seizure of the substance in the country's history.

Suspicious Australian Border Force investigators allegedly found 2000 litres of the drug gamma-butyrolactone in 10 large drums hidden within a shipping container full of 120 drums of "car pre-paint wash" when it arrived at Port Botany earlier this month.

A Warwick Farm man, 30, was arrested on Friday during a series of raids across Sydney and charged with importing a commercial quantity of a border controlled substance.

He was due to face Liverpool Local Court later on Friday.

Although more tests needed to confirm the purity of the seizure, authorities have estimated the street value of the drug at $10 million.

Once in the body, GBL metabolises into the drug gamma-hydroxybutyrate (GHB), which is also known on the street as a shortened version of grievous bodily harm (GBH).

It can cause abrupt loss of consciousness, memory loss, respiratory difficulties, coma, and death.

Australian Federal Police State Manager NSW Commander Chris Sheehan said despite users believing GBL was a harmless "party drug", the "reality were much more dangerous".

"What people are actually ingesting is an industrial chemical solvent. The World Health Organization says it is the kind of substance commonly found in paint strippers, stain removers, and circuit board cleaners," Commander Sheehan said.

"This 'coma in a bottle' affects a person's consciousness – predators have used it to enable rape.  It is vital we continue to work with our partners at the border to stop any dangerous drug that can contribute to these sorts of crimes in our community."