The only crossing between Gaza and Egypt opened on Tuesday for 72 hours, allowing people to leave the Palestinian enclave for the first time since the outbreak of the novel coronavirus.
The Rafah crossing in southern Gaza was closed in March, as Hamas - the group that administers the Gaza Strip - sought to guard against a major virus outbreak in the densely populated territory with weak health infrastructure.
Rafah was opened in April for three days, but only to allow Gazans stranded abroad to return home.
Gaza's interior ministry spokesman Iyad al-Bazam said people who hold foreign passports, foreign residency permits or emergency medical needs "will be allowed to leave".
Hundreds of Gazans had assembled before dawn in a waiting area, preparing to exit.
Gaza resident Hatem al-Mansi told AFP that while he needed medical care, he was worried about the possibility of coronavirus infection in Egypt, which has registered 95,000 cases, compared with just 81 in Gaza.
"There is a fear of being infected with COVID-19 in cars or buses in Egypt," he told AFP. "In Gaza, we don't have that problem."
Anyone returning from Egypt will be placed in a dedicated quarantine facility for three weeks, said the head of infection control at Gaza's health ministry, Rami Al-Abadala.