Police and customs officers have uncovered an illegal moonshine factory in two units on an industrial estate.
Officers want to trace the drink which has already been distributed
Four men have been arrested, HM Revenue and Customs (HMRC) said on Friday.
Illegally distilled whiskey and vodka was discovered in the units in Oldham, Greater Manchester, along with money, a bottling plant and equipment.
It is estimated that the duty owed on the drink seized was £690,000, but the total loss to the HMRC could be several million pounds, it says.
HMRC is working with police and trading standards officers to trace the illegal spirits already distributed.
Labels on the bottles, which may be offered for sale, include Royal Czar Imperial vodka, Tamova vodka, Imperial Stag Whiskey, Kommissar, Glens and Hanacka vodkas.
The men arrested - three from Oldham and one from Mossley - have been released in bail, pending further inquiries.