More than 100 patients, including children suffering from trauma injuries and chronic diseases, will be evacuated from Gaza on Wednesday in a rare transfer out of the Gaza Strip, a World Health Organization official said.

"These are ad hoc measures. What we have requested repeatedly is a sustained medevac (medical evacuation) outside of Gaza," said Rik Peeperkorn, WHO representative for the Occupied Palestinian Territory, adding that 12,000 people were awaiting transfer.

The patients will travel in a large convoy on Wednesday via the Kerem Shalom crossing with Israel before flying to the United Arab Emirates, he added, and then a portion will travel to Romania.