Emergency aid efforts can be marred by "turf wars" between medical relief groups and development agencies, a leading medical charity figure says.
Priorities can differ when disasters occur
Medecins Sans Frontieres executive director Gorik Ooms said differing priorities could lead to clashes.
Writing in the Public Library of Science journal, he said development agencies and governments often insisted on long-term sustainable measures.
This sometimes meant they tried to block short-term health aid in crises.
He said: "The problem is that there is a conflict with what we are trying to achieve with health care.
"Development agencies want their interventions to be sustainable. That is to say, the host country has to be able to maintain the programme.
"However, in times of emergency sustainability is irrelevant as the crisis is by definition temporary and the need for relief will ebb with the crisis."
Mr Ooms cited several examples of where relief efforts had been hampered, although he did not name the development agencies involved:
During the flooding in Mozambique in February 2000, Medecins Sans Frontieres (MSF) officials involved in the helicopter rescue wanted to provide antiretroviral drugs to help people with HIV/Aids but development agencies initially opposed it
MSF also encountered resistance in its efforts to provide free health care during the recent food crisis in Niger, with development agencies believing providing free care would undermine attempts to build up a health insurance system
MSF has published a report on the Democratic Republic of Congo showing subsidised health care is needed but this has "fallen on deaf ears"
Mr Ooms said health development agencies, which he classed as government departments and NGOs, needed to accept that sometimes immediate need conflicted with long-term goals.
"Medical relief organisations are not driven by health development approaches. Instead, they are driven by a humanitarian impulse - there are overwhelming needs and there is an obligation to respond to those needs."
A spokesman for Health Action Network, an umbrella group involving development agencies which aims to increase access to medical treatments, said some of the actions seemed "harsh".
But he added: "It seems to be a question of communication and integration. Perhaps relief groups could look to try to work with the development agencies to create a more sustainable legacy for their relief work."
And the Department for International Development (DFID) said: "As both a development agency and an organisation funding humanitarian relief, DFID believes that caring for the poorest, most vulnerable people in the world means providing long-term assistance but also giving a helping hand in emergencies.
"The demands and aims of emergency relief and long-term development may not always be identical but they both meet the need of reducing poverty and suffering."