An Adelaide teenager has been charged by police in connection to the "largest seizure ever" of lysergic acid diethylamide (LSD) in South Australia.

Key points: Police allege the teenager arranged to have the drugs sent to an address in Adelaide

Police allege the teenager arranged to have the drugs sent to an address in Adelaide The estimated street value of the drugs is about $300,000, police say

The estimated street value of the drugs is about $300,000, police say He has been charged with trafficking a large commercial quantity of a controlled drug

Police will allege Brenton Mackenzie Skanes, 18, attempted to traffic 20,000 tabs of LSD, and bought the drugs over the dark web.

The court heard he had arranged to have "tickets" of the drug sent through the post to an address in the Adelaide CBD from the Netherlands.

The teenager from Marion, in Adelaide's south, was arrested on Wednesday by detectives from the South Australian Joint Agency Strike Team (JAIST) and the SA Police Serious and Organised Crime Branch.

He was charged with trafficking a large commercial quantity of a controlled drug.

Detective Chief Inspector Tony Crameri said the drug bust was the largest seizure of the drug in the state and had a street value estimated to be about $300,000.

He also said seizures of this size were "very rare" by police anywhere around the world.

"This is a highly-dangerous hallucinogenic drug which can have long-term health effects on the user," he said.

"Someone importing a drug like this from Europe is risking their health and liberty with drug manufacturers only interested in profit."

Skanes appeared in the Adelaide Magistrates Court on Thursday afternoon and applied for bail.

Magistrate Alfio Grasso said he would consider granting bail when the case returned to court on Friday.

In applying for bail, the teenager's lawyer James Caldicott told the court the package was not addressed to his client.

He said the teenager was a young man with good family support and his mother was willing to be a bail guarantor.

The prosecution alleged the teenager collected the package, sent from the Netherlands, from a Franklin Street post box facility.

It is alleged the dual Australian-Canadian citizen used his Canadian passport and driver's licence as identification.

Magistrate Grasso said he was "minded to grant bail" to the teenager but adjourned the hearing until Friday to seek clarification about whether both the accused's passports had been seized.

'The AFP will catch, arrest and prosecute you'

AFP operations coordinator Superintendent Gail McClure said a strong relationship between the AFP and its domestic partners had led to the record drug bust.

"Working in partnership with South Australia Police and other JAIST agencies allows us to prevent these drugs from getting onto Australian streets and causing harm to our communities," she said.

Evidence collected by NSW Police over an alleged drug syndicate that traded on the dark web. ( Supplied: NSW Police )

"This operation should send a strong warning to criminals that if you participate in illegal activities, the AFP will catch, arrest and prosecute you."

Earlier this year in a separate case, NSW Police said they had penetrated a $17 million drug syndicate operating on the "dark web" shipping drugs, some of which were disguised as lollies.

Officers said they raided several locations on the NSW south coast, seizing 2.5 kilograms of white powder, 200 grams of MDMA, 100,000 LSD tabs and a significant quantity of Xanax.

A 25-year-old man and two women, aged 24 and 20, were arrested and charged with a range of drug offences.

Police said if the public had any information regarding anyone involved in buying or importing drugs via the dark net, they should contact Crime Stoppers on 1800 333 000.