Reports from Somalia say the United Arab Emirates has stopped issuing visas to holders of Somali passports.
Much of Somalia is in ruins after years of fighting
The BBC's Daud Aweis in Mogadishu says this will have a huge effect on war-torn Somalia, because most imports come through the UAE.
Somalis also go to the UAE for medical reasons, or when travelling to Europe.
Kenya stopped issuing visas to Somalis last month, complaining passports were being widely forged in the absence of a central government in Somalia.
Somali travel agents said they had been informed of the decision by letter.
The letter said the measure would come into force immediately, but did not explain the reasons behind it.
UAE has not yet confirmed the ban, or explained the reasons behind it.
The ban apparently came to light when officials of Somali travel companies were denied visas, reported the Somali HornAfrik Online website.
They were also issued letters informing them of the UAE's decision to stop issuing visas to holders of Somali passports with immediate effect, it reported.
Reports suggest forged passports are available in the markets of the capital, Mogadishu, for as little as $25, and in the Kenyan capital, Nairobi.
Kenya cited security concerns and illegal migration when it banned visas for Somalis in April.
Numerous other countries do not recognise Somali passports.
The country has been without a central government since 1991, when the then president Siyad Barre was ousted.
A transitional government was established in 2000, but has little control outside Mogadishu.
Long running talks have been taking place in Kenya to try to establish a new government.