"The amounts that are coming in will keep us going for about 20 days."
Ging said that a special concession was made to lift the blockade by Israel for the UN, as with one power plant in Gaza, but that otherwise no one else in Gaza was receiving fuel.
"That's a real problem. It's affecting every aspect of human life here in Gaza."
He added that the situation was deteriorating every day, with waste, water supply and transport problems endemic.
"Now the estimate is that 60,000 litres [of raw sewage] per day is being pumped into the sea simply because there is no fuel to run the plant that's needed to treat that sewage," he told Al Jazeera.
The agency resumed distributing aid in the besieged Palestinian territory only last Tuesday after a four-day interruption also caused by fuel shortages.
Mike Hanna, Al Jazeera's correspondent in Gaza, had said that the fuel crisis was, "a very dire situation indeed. Seen in a wider context, this is just one issue that is plaguing Gazans every single day."
Cars in Gaza, lacking fuel, have largely begun using a mixture of petrol and cooking oil.
Hanna said: "The dangers of this are obviously its going to shorten the life of the engines, but also, these are time bombs on the road. At any stage, one of them could explode, creating great loss of life.
"In the wider scheme of things, the situation in Gaza is absolutely desperate. This is a humanitarian crisis."
Israel previously closed the Nahal Oz border crossing and fuel terminal after two Israelis were killed in an attack, causing an acute shortage of fuel in Gaza.
Israel imposed a punishing blockade on the Gaza Strip after Hamas took control of it nearly a year ago, allowing only a minimum of basic supplies through the crossings.
It says it will only consider easing the blockade if there is a complete end to cross-border attacks by Palestinian armed groups.
'Overcome security challenges'
Ging said that the UN condemned the attacks by Palestinian groups.
"That has to stop. That is one of the reasons why it is so difficult to get fuel into Gaza.
"But there's a civilian population here [in Gaza] who are also victims of this conflict and solutions have to be found to overcome these security challenges.
"They have been overcome for us the UN. They have been overcome for the power plant.
"And now they need to be overcome for the rest of the civilian population to restore them some dignity to their existence here."
In Cairo last month, 12 Palestinian factions, including Hamas, agreed to observe a six-month ceasefire, on condition that Israel end the blockade and stop its cross-border raids.
Hanna said: "Effectively each side is insistent that improving the situation in Gaza is dependent on action by the other, a fundamental disagreement about what should come first."