Silvestre Bello said there was no plan yet to repatriate the more than 200,000 Filipino workers in Qatar.
"If anything happens and they run out of food and food riots take place, definitely our OFWs will be the first victims," Bello said, using the acronym for overseas Filipino workers. "We need to adopt preparatory measures to meet the possible exigency."
Filipino officials and recruitment agencies have been asked to ensure that Filipino workers in Qatar are safe and have adequate food stocks.
Saudi Arabia and three other Arab powers severed diplomatic ties with Qatar yesterday and moved to isolate it, accusing it of supporting terrorist groups and backing Iran.
Qatar has long denied supporting militant groups.
Saudi Arabia closed its land border with Qatar, through which the international travel hub imports most of its food, sparking a run on supermarkets.