Gardai have seized more than half a million BZP tablets since the ecstasy replacement was banned from head shops last year.
The party drug was made illegal in April 2009 but new figures suggest that it has now become a popular street drug.
Figures released by the Department of Justice show that gardai have seized €3m worth of Benzylpiperazine, more commonly known as BZP, in the 12 months since.
The value of the BZP discovered by gardai so far in 2010 is on a par with the amount of cannabis resin and cocaine.
The statistics will heighten fears that other so-called legal highs banned by the Government earlier this month will now also result in former users dealing with black market drug pushers.