Gaza's largest desalination plant will be operational in the autumn as the Palestinian enclave tries to avert a potential humanitarian crisis over a lack of drinkable water, officials said Tuesday.

A 2012 UN report warned that over-extraction of groundwater from the Gaza Strip's sole aquifer could make it unusable by 2016, while the damage could become irreversible by 2020.

In response, the European Union and the UN children's agency, UNICEF, have financed construction of a desalination plant in the south of the enclave of 1.9 million people, including around a million children.

Most water plants in the Gaza Strip draw from groundwater, not from the sea.

Tests on the desalination plant in Deir el-Balah will be carried out in the summer, with the aim of producing 6,000 cubic metres of drinking water per day.

That amount would be doubled over the course of three years.

Eventually, "150,000 Palestinians living in Rafah and Khan Yunis (in southern Gaza) will have access to fresh drinking water" through the project, EU Enlargement Commissioner Johannes Hahn said Tuesday.

"Nearly 95 percent of the water resources in Gaza are considered unfit for human consumption," he said.

With the coastal enclave under an Israeli blockade for around a decade and hit by three wars with Israel since 2008, Gazans "have witnessed a rapid decline in living standards, including the lack of crucial access to fresh water and to reliable sources of power," he added.