The office said in a statement the opening would allow Israel to maintain its commitments to permit the entry of 200 trucks of aid per day, agreed upon in a hostage deal brokered and implemented last month.
The crossing had been closed after an Oct. 7 attack by Hamas and aid was being delivered solely through Gaza's Rafah crossing with Egypt which, Israel said, could only accommodate the entry of 100 trucks per day.
U.S. national security adviser Jake Sullivan welcomed the decision to open the crossing, which he called a "significant step", saying the White House hoped it would ease congestion and help facilitate the delivery and distribution of humanitarian aid through Rafah.
The World Health Organization also welcomed the move as "good news."
Kerem Shalom, on the border of Egypt, Israel and Gaza, is one of the main transit points for goods in and out of Gaza, allowing much faster transit than the Rafah passenger crossing a few kilometres away.
Israel had already agreed to allow trucks to be inspected at Kerem Shalom but the trucks had previously been obliged to return to Rafah, to cross into Gaza from Egypt and aid groups had been calling for them to be allowed in directly.
As Israel's campaign in Gaza has continued, the humanitarian situation in the besieged enclave has worsened dramatically with the United Nations and other world bodies warning of severe shortages of food, clean water and medicines.
UN agencies say that as the bombardment has continued, it has become impossible to distribute aid outside Rafah, where the population has been swollen to around 1 million with hundreds of thousands of refugees coming from areas further north.
(Reporting by Emily Rose, Editing by William Maclean and Grant McCool)
