ISTANBUL - Many aid groups have become "big bureaucracies" and need help to slim down in order to help the growing number of people in need, a key EU commissioner said Tuesday.

A so-called "Grand Bargain" launched at the World Humanitarian Summit in Istanbul aims to make aid more effective by reducing the bureaucracy of aid groups and keeping down the demands of donors on them in return.

Kristalina Georgieva, European Commissioner for budget and human resources, who launched the plan at the summit, said the rethink was needed given the "exponential growth" of people in need.

"If they were a country today with a population of 130 million this would be the 10th largest country in the world, between Russia and Japan, and it would be the fastest growing country," she told AFP in an interview at the summit.

"What the Grand Bargain is is mutual accountability so we can move more resources into the hands of people who need and the humanitarian workers risking their lives to help them, and less in the back room."

She said that as a result of the increasing demands and also budgets with total aid now reaching $28 billion, humanitarian organisations have been struggling to cope.

"They have not taken time to say 'do we work the right way?'. They used to be small agile organisations, now they are big bureaucracies," she said.

"It is absolutely essential not just to raise more money but to use better the money that we raise."

She said humanitarian groups had been growing at a fast pace and "without due consideration" of how to use resources in the best possible way.

Bigger budgets "also has led to an increase of overheads, some overlaps, competition among agencies. We have to address that," said Georgieva.

The Bulgarian added: "Donors are also part of the problem. Donors created more reporting requirements and demands and have not been modernising humanitarian aid."

The Grand Bargain is a set of mutual commitments set out by donors and aid groups to make the process of getting aid to those most in need more effective.

It can also encourage smaller grassroots NGOs who can sometimes deliver aid more effectively on the ground and take some pressure off the big UN agencies.

The question now is whether it can be implemented.

"I have faith and will because the pressure to get help to people is so enormous and will only continue to grow," said Georgieva.

"But it will require mutual accountability to work. In the next months we will see how we follow the benchmarks."