Tuesday's alert by the Integrated Food Security Phase Classification follows an outcry over images of emaciated children in Gaza and reports of dozens of hunger-related deaths.
The IPC made the warning in an "alert," or update, that falls short of a formal famine declaration. But it says recent developments, including a tight blockade by Israel, have "dramatically worsened" the situation.
Israel has announced new steps in recent days aimed at increasing the flow of food into Gaza. But aid groups say the measures have had little immediate impact.