People in some of the world’s worst conflict zones believe the presence of humanitarian organisations is declining even as their need for them increases, according to an investigation into the impact of violence and insecurity on relief efforts.

Researchers also found that incentives to highlight the presence of such organisations on the ground to the general public and donors meant they sometimes overstated their impact, inadvertently making humanitarian situations appear less dire than they were.

The findings, based on three years of field work in Afghanistan, Somalia, South Sudan and Syria, emerged from the secure access in volatile environments (Save) project, funded by the Department for International Development and undertaken by the Humanitarian Outcomes consultancy and the Global Public Policy Institute, a Berlin-based thinktank.

Only in Somalia and one Syrian province did most people surveyed perceive an increase in the number of aid agencies operating.

The study comes at a time of acute concern about the security and safety of aid workers, including local staff, in humanitarian situations. NGO staff were assaulted and raped during an attack on aid workers in South Sudan in August that left at least one person dead.

As access becomes more difficult in “high-risk countries”, aid is becoming more basic and less responsive to the critical needs of the most vulnerable people, the project found.

“In high-risk countries aid agencies tend to narrow their field presence and cluster in safer areas,” said the researchers. “Only a small group of humanitarian organisations operate in the highest-risk places. Surveys of people living in high risk areas say that aid is declining even as their needs are rising.”

The researchers warned that donor policies and incentives can work against humanitarian access and coverage, making the aid presence seem more robust than it is, and also said that the independence of agencies was threatened by counter-terror policies and funding strategies that have the effect of discouraging aid programming in opposition-held territories.

The release of the research coincided with the publication of a report by Katherine Haver, a partner at Humanitarian Outcomes, into the ethical choices facing humanitarian organisations in zones where conflict makes it dangerous for aid workers to operate safely.

The study highlighted concerns among the senior staff of some NGOS about the duty of care to local workers, upon whom many international organisations are increasingly reliant.

Haver found that national partners in Somalia, Syria, South Sudan and Afghanistan were taking on more security risks, but often with insufficient support. “They saw the main risks as coming from aerial shelling and military clashes, and simply attempted to move staff away from possible strike locations,” she said.

Humanitarian action had the potential to do harm rather than good, added Haver. Examples of this risk included threatening to stop or withdraw services.

In South Sudan, organisations suspended operations in specific areas as a way of dealing with riots, interference by local authorities or threats to staff. “Some aid staff saw this as a form of collective punishment, whereby those not involved in the incidents were inappropriately denied aid,” said Haver.