The United Nations refugee agency called on states today to give shelter to people fleeing Somalia even if they do not meet formal refugee criteria.
The UNHCR said it was changing its guidelines, which influence government policies, because it believed asylum seekers from central and southern Somalia needed international protection.
The move reflects the gravity of the humanitarian crisis in a country where lawlessness has allowed pirates to attack shipping in the Gulf of Aden, a major artery for oil cargoes.
Al Shabaab Islamist rebels have been fighting Somalia's western-backed government since early 2007 and now control much of southern and central Somalia, hemming the government into a few blocks of the capital, Mogadishu.
"Conditions in Somalia have been steadily deteriorating for some time and are particularly acute in the central and southern areas of the country," UNHCR spokeswoman Melissa Fleming said.
People displaced by the fighting between the government and different rebel groups had little chance of relocating in central or southern areas, or finding shelter in the northern breakaway region of Somaliland or the semi-autonomous province of Puntland, she told a briefing.
Somalia already has 1.4 million internally displaced people, and about 575,000 have fled to neighbouring countries. In 2009 Somalis were the third largest group of asylum seekers in industrialised countries, with more than 22,000 claims, after Iraq and Pakistan, according to figures from the UN High Commissioner for Refugees.
UNHCR is urging countries to take in refugees on a group basis if they cannot process individual applications.
That could involve giving people temporary shelter even if they do not get full asylum status - an approach used by European countries during the war in Bosnia.
"It is our view that involuntary returns to central and southern Somalia under today's circumstances would place individuals at risk," Ms Fleming said.
Kenya, Ethiopia, Eritrea, Djibouti and Yemen are already taking in Somalis on a group basis, she said.
The UNHCR is in talks with the government in Kenya to help it improve screening. Kenya has officially closed its border to Somalia, although 17,000 people have arrived so far this year, she said.
As the Arab world's poorest country, itself beset by conflict, Yemen is hardly an attractive destination and refugees must risk a voyage across the pirate-infested Gulf of Aden to get there, but some are still choosing that option.
The new UNHCR guidelines broaden categories of people at risk in Somalia to include groups such as supporters of the government, individuals seen as in conflict with Islam, civil society workers, journalists, minority clans and religious groups, and women and girls.
Reuters