A “technical error” meant that Thailand falsely declared it had seized nearly $1bn worth of ketmaine from a warehouse.
The Justice Minister Somsak Thepsuthin revealed on Tuesday that the substance was actually trisodium phosphate, a compound commonly used as a cleaning agent.
Officers from the Office of Narcotics Control Board (ONCB) seized 475 sacks of a white, granular substance during a raid on a warehouse in the Chachoengsao province in south-central Thailand on November 12.
The raid was ordered after the ONCB received a tip-off from Taiwan which Mr Somsak had an “undeniable link” to ketamine.
According to a report by The Nation, ONCB secretary general Wichai Chaimongkhol told reporters after the bust: “The drugs are the largest amount ever seized in Thailand, with [an] estimated value [of] 28.7bn baht ($950m; £710m) based on retail price.”
Samples taken from the sacks turned testing fluid purple, leading authorities to declare Thailand had successfully seized 11.5 tonnes of ketamine - the country’s largest ever haul of the drug.
But according to the Bangok Post, the mix up occurred as preliminary tests which turn purple in the presence of ketamine hydrochloride also react the same to trisodium phosphate.
On Tuesday Mr Somsal told a media briefing a “technical error” in field testing had led to the false claim.
"This was a misunderstanding that our agency must accept," Mr Somsak told reporters.
He added: “No matter, we have admitted the mistake, and it may not be corrected in the short term.”
Mr Somsak said he accepted all criticism after being asked if the blunder could affect the credibility of the Justice Ministry and the ONCB.