ICRC spokesperson Inji Sedky told Xinhua that the convoy, which was due to arrive on Thursday, was postponed to an unknown date due to the evolving situation on the ground.
The situation in Eastern Ghouta on the outskirts of the capital Damascus "doesn't allow us to move forward with the operation under such conditions," she said.
The first shipment of 46 truckloads of aid entered the rebel-held Douma district in Eastern Ghouta on Monday, the first such aid to reach that area since the UN Security Council adopted a resolution on a 30-day humanitarian ceasefire in Syria on Feb. 24.
However, activists said that 14 of the 46 trucks couldn't be offloaded in Douma due to the shelling on that area.
UN humanitarian agencies have sounded the alarm about the worsening humanitarian situation in Eastern Ghouta, where activists said over 800 people have been killed since late last month by intensified shelling and fighting between government troops and the rebels.
The Syrian army has captured 52 percent of Eastern Ghouta in recent days, as part of an ongoing large-scale offensive to dislodge the rebels from the area.