Drone footage showed endless lines of cars along the roads leading to testing centres in Jerusalem and Ashdod.
Daily cases in Israel are expected to reach record highs in the coming three weeks.
Israeli prime minister Naftali Bennett said that up to 50,000 people might soon be infected each day, while eligibility for testing could be tightened to help relieve long lines at testing stations.
Israel's health ministry says around 60% of its 9.4 million population are fully vaccinated, almost all with the Pfizer-BioNTech vaccine, which means they have either received three doses or have recently had their second.
But hundreds of thousands of those eligible for a third inoculation have so far not taken it.
Over the past 11 days, daily infections have more than quadrupled in Israel. Severe cases have also climbed, but at a far lower rate, rising from about 80 to around 100.