Thousands of bars, restaurants and shops were raided by the Czech police after methanol poisoning caused by bootleg spirits left 19 people dead and others seriously ill.
As 20 people remained in hospital, some in artificial comas or going blind, police said they checked over 19,000 premises overnight Friday to Saturday and seized "suspect" alcohol in 14 locations.
A health ministry analysis showed most of those affected had drunk one of two types of tainted liquor -- vodka or a local rum dubbed "tuzemak".
The measure followed a ban earlier in the week on spirits with over 30 percent alcohol being sold by street vendors and market stalls, although authorities said most of the victims obtained the alcohol from shops, bars or eateries.
The head of the spirits producers and importers union, Petr Pavlik, criticised the ban, saying it would encourage black marketeering.
Thirteen people had so far been charged in connection with the bootleg alcohol, police said.
"The police carried out more than 19,000 checks between Friday evening and 6:00 am (0400 GMT) on Saturday," Prague police spokesman Tomas Hulan told AFP.
Although police believe an organised network might be responsible, so far no hard evidence had been found, according to deputy national chief of police, Vaclav Kucera, in charge of a special task force investigating the case.
"For the moment we have no confirmation that the production is organised in greater depth," Kucera told Saturday's edition of the Lidove noviny broadsheet, adding that the primary cause could be the "infiltration of low-quality material into the network of local bootleggers".
Doctors have been administering fomepizole, a costly methanol antidote imported from Norway.
The ban is the first ever imposed in the Czech Republic, an ex-communist state of 10.5 million, which has the world's second highest adult alcohol intake after Moldova, according to latest World Health Organisation data.
Shop and restaurant owners who flout the ban face a fine up to three million koruna (123,000 euros, $162,000).
The wave of poisonings has spread across the country since killing two people on September 6, hitting Prague on Friday when a 30-year-old man was hospitalised in a serious condition.
The man had been drinking in several bars in central Prague, according to police who found "dozens of bottles whose customs stamps had been tampered with" in bars in the centre of the Czech capital.
Heger said the ban, which forced some bar and shop owners to remove spirits bottles from bars and shelves, could be in force for "several weeks."
The northeast of the Czech Republic has been hit particularly hard, with 11 deaths there from the tainted alcohol.