George Galloway, a British politician leading the convoy, had appealed to Egyptian authorities to grant the lorries access to Gaza through the Red Sea port of Nuweiba.
But Egyptian authorities had insisted that the aid be delivered through its Mediterranean port, a much longer journey that requires the convoy to go around the Sinai peninsula and through the Suez Canal.
Organisers of the convoy eventually agreed, and they are expected to reach El Arish on Monday, before crossing into Gaza.
Viva Palestina and another convoy, the Gaza Freedom March, were scheduled to arrive in Gaza on December 27 to commemorate the first anniversary of Israel's war on Gaza that killed 1,400 Palestinians and 13 Israelis.
The Viva Palestina convoy is expected to deliver European, Turkish and Arab aid - both food and medical supplies - to Gazans affected by an Israeli blockade on the Strip.
Israeli enacted the siege after a Hamas election victory and the group's push of 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.