The Viva Palestina convoy, containing some 210 vehicles and 500 people, is currently stranded in Jordan with Cairo refusing to allow it passage to Gaza through the Red Sea port of Nuweiba.
The lorries are laden with European, Turkish and Arab aid - both food and medical supplies.
"It's a strange Christmas for us. We are stuck ... hundreds of tonnes of aid which is desperately needed in Gaza," Galloway said in an interview with Press TV on Friday.
"We are very sad not yet angry, but we will get angry if the days go by".
But Hossam Zaki, an Egyptian port official, insisted that there would be "no entry from Nuweiba", saying "entry can only be through El-Arish".
El-Arish is a port on Egypt's Mediterreanean coast, while Nuweiba is on the Red Sea.
The Egyptian decision means the convoy would have to travel hundreds of kilometres by ferry around the Sinai peninsula and through the Suez Canal.
In a statement, the Egyptian foreign ministry said: "The Egyptian government welcomes the passage of the convoy into the Gaza Strip on December 27, on condition that it abides by the mechanisms in place for humanitarian aid convoys to the Palestinian people.
"This includes most importantly, the entry of convoys through the port of El-Arish".
Gaza has been under a stifling Israeli siege since a Hamas election victory and its decision to push Fatah armed forces from the territory in June 2007.
The blockade has severely restricted essential supplies and placed Gazans in a dire situation, made worse by Israel's military assault last winter that reduced much of the territory to ruins.
According to the latest UN report on the situation in Gaza, the ongoing Israeli blockade has triggered a "protracted human dignity crisis" with negative humanitarian consequences.
"At the heart of this crisis is the degradation in the living conditions of the population, caused by the erosion of livelihoods and the gradual decline in the state of infrastructure, and the quality of vital services in the areas of health, water and sanitation, and education,” adds the report.