Laboratory testing has confirmed $20,000 worth of "herbal incense" products seized by ACT police contain synthetic cannabinoids.
The substances, believed to include popular marijuana substitutes such as Kronic and Jungle Fever, were available for sale through tobacconists, sex shops and other retail outlets.
Because they were not illegal at the time, the products could be sold to anyone, regardless of age.
This is despite the fact habitual drug users have told Fairfax the substitutes are more potent and more addictive than marijuana.
ACT Policing has also seized at least one product from a Canberra shop that is suspected to contain synthetic cathinones.
Cathinones can be used as a substitute for amphetamines or "speed".
The Federal government banned 19 synthetic drugs earlier this month after they were linked to the death of a Sydney teenager. Henry Kwan, 17, plunged to his death from a balcony.
He had bought an LSD-substitute on the internet and, after taking it, apparently believed he could fly.
The Australia-wide ban is in effect for 120 days and is designed to provide a respite to allow state and territory governments time to update their legislation to keep "synthetics" off the open market.
Products affected include White Revolver, Buddha Express Black Label, Ash Inferno, Kyote, K2, Black Widow, Skunk, Kronic, Vortex Inferno, Herbal Incense, Tropic Thunder, King Karm and Circus Deluxe.
Off Ya Tree's Canberra branch was abiding by the ban. Staff were telling customers on Friday substances such as Jungle Fever were not available because of it.
Zoe L., a recreational drug tester with Perth's The Broke Stoners website, said the synthetics should be banned rather than just taken off the market for four months.
"It is quite frankly a joke that anyone can buy such a powerful damaging synthetic at our local corner deli, right next to the tobacco cabinet," she said.
"They need to make it illegal, keep it illegal and, if anything, make marijuana legal or at least decriminalised.
"Prevention would be more inclined to work. I haven't seen any education being provided to the public [about synthetics]. Shouldn't prevention have started months ago?
Zoe said she had learnt the hard way that synthetics were very dangerous.
"How many deaths is it going to take before the government decides to do something about it?" she said.
"We can honestly say we see how addictions can occur, also it can lead to stress, anxiety, paranoia and anger. We [Zoe and partner Corey] both have experienced this.
"Synthetic companies were literally handing it out to us for free for the sake of a review and more sales. We quit synthetics cold turkey. If we had continued we would have ended up with some severe mental and physical addictions."
Where Zoe and Corey part company with the state and federal governments is on the subject of "real" marijuana.
"We have been regularly smoking marijuana and we highly [sic] support the legalisation of the plant."
Zoe said claims by some stores that the synthetic products weren't meant to be smoked were absurd.
"If you are not supposed to smoke it then why is there such a large amount of synthetic THC in the product?"