Mr Egeland revealed that the UN had presented all the warring parties and their backers last week with a four-point initiative for getting aid to eastern Aleppo.
The plan would involve medical evacuations for about 300 patients in urgent need, delivery of food and medical supplies, and permission for medical personnel to enter the city.
Mr Egeland said he was confident that access would be granted because "the consequences of no help and no supplies will be so catastrophic I cannot even see that scenario".
Hundreds have died since the government launched an assault on eastern Aleppo in September
But he admitted that he had never seen such "politicisation and manipulation" of aid as was taking place in Syria, adding that the constant preconditions being imposed on aid operations were making successful deliveries of supplies impossible.