The Lebanese flour millers' association said on Tuesday fuel shortages were threatening bread production and mills would gradually stop working after supplies ran out.
Lebanon's financial meltdown has translated into crippling fuel shortages that have paralysed many aspects of daily life.
The state power generator has barely supplied any electricity, leaving Lebanese households and businesses increasingly reliant on private generators powered by fuel oil, which in turn is in short supply.
"The association is calling out to all concerned officials to work quickly before it is too late, fuel oil supply for all the mills has run out and they may stop working gradually starting today," a statement from the association said.
Despite efforts, alongside the economy and trade ministry, to communicate concerns to several officials, "no positive results have been reached", the statement said.
Lebanon's economic crisis, described by the World Bank as one of the deepest depressions of modern history, has seen its currency lose more than 90% of its value and propelled more than half of its population into poverty.
The fuel crisis reached a crunch point this month when the central bank said it could no longer finance fuel imports at heavily subsidised exchange rates and would switch to market rates.